10  19' 

REPORT 


ON  THE 


DAM  AND  WATER  POWER 
DEVELOPMENT 


AT 


AUSTIN,  TEXAS 


BY 

DANIEL  W.   MEAD 
NOVEMBER,   1917 


DANIEL  W.  MEAD 
CHARLES  V.  SEASTONE 

CONSULTING  ENGINEERS  * 

MADISON,  WISCONSIN 


REPORT 


ON  THE 


DAM  AND  WATER  POWER 
DEVELOPMENT 


AT 


BY 

DANIEL  W.   MEAD 
NOVEMBER,   1917 


DANIEL  W.  MEAD 
CHARLES  V.  SEASTONE 

CONSULTING  ENGINEERS 
MADISON,  WISCONSIN 


-v 


/$> 


A, 


<N 


TABLE  OF  CONTENTS 

Page 

Letter  of  Transmittal  1 

Instructions    3 

Resolution    3 

Acknowledgments    5 

REPORT  ON  THE  DAM  AND  WATER  POWER  DEVELOPMENT  AT  AUSTIN,  TEXAS 

Method  of  Financing    7 

Plans  and  Specifications    9 

The  Reconstruction  Work   9 

The  Contractor  for  the  Work   9 

The    Bond    Issue    11 

Work  Apparently  Nearing  Completion    11 

Difficulties   Arise    11 

Financial    Collapse    i2 

Period  of  Investigation    12 

Physical  Conditions  at  the  Dam  Site  12 

The   Old  Dam    14 

The  New  Structure   14 

Plans  and  Specifications   15 

Changes   in   Plans    15 

THE  EFFECTS  OF  CHANGES  IN  PLANS  AND  SPECIFICATIONS 

Betterments    16 

Immaterial    Changes    19 

DETRIMENTAL  CHANGES 

Detrimental  Changes  in  the  Provisions  for  a  Safe  Foundation 20 

Grouting    20 

Cut-Off  Wall  above  West  Section  of  the  Old  Dam  20 

Cut-Off  Walls  in  Reinforced  Concrete  Dam   20 

Detrimental  Changes  in  the  Structures  of  the  Dam  and  Appurtenances 21 

Core   Wall    21 

Pointing   the   Old   Dam    21 

Changes  in  Gates  and  Setting   21 

Sluice  Gates  and  Sluice  Gate  Trash  Racks   21 

Power  Plant  Accessories   21 

The   Tail   Race    21 

Penstocks    23 

Fourth    Penstock    23 

Draft  Tubes   23 

DEFECTS  IN  PRESENT  CONDITIONS  AND  STRUCTURES 

Foundation    Conditions    23 

Foundation     24 

Riverbed  below  the  Dam    24 

Leakage    24 

The  Structure  of  the  Dam  27 

Old  Dam  Section    27 

Crest   Gates    27 

Sluice    Gates    27 

Passageway  in  the  Dam  27 

Plant    Accessories 29 

Head  Gate  Masonry  29 

Head  Gate  Trash  Racks  29 

Head   Gate   Hoists    29 

Tail  Race    29 

Draft    Tubes 29 

Pumps    29 

Station  Equipment,  Etc 29 

REMEDIES 

Foundation  Conditions    29 

Foundation  at  the  Heel  of  the  Dam  29 

Leaks  under  the  New  Section    29 

Improvements  below  the  Toe  of  Dam   30 

Dam   Structure    30 

Crest  of  Dam    30 

Old  Dam  Section    30 

Reduction  in  Seepage  around  Dam  30 

Walk  in  Dam    30 

Sluice  Gates  and  Sluiceways   30 


383394 


vi  Table  of  Contents. 

Inspection  of  Foundation  under  Dam   30 

Plant    Accessories    • 

Head   Gate   Masonry    

Head  Gate  Trash  Racks  30 

Tailrace    31 

Deflecting    Wall    

Railing    

Estimated  Cost  of  Betterments,  Changes  and  Improvements   31 

Character  of  the  Estimate   32 

Permanency  of  the  Structures  32 

Value  of  Material  and  Labor  in  Place  

Responsibility  for  Cost  of  Betterments   

Ultimate  Value  of  the  Plant   38 

Supervision  of  the  Construction  of  Betterments   39 

APPENDIX  1 
HISTORY  OF  THE  AUSTIN,  TEXAS,  DAM 

Beginning  of  Active  Work  40 

Change  in  Plans   42 

Data   on   the   Completed    Dam    44 

Development  of  Leaks  in  the  Foundation   47 

Warnings   of   Disaster    48 

The  Silting  of  the  Reservoir   49 

The  1900  Failure   53 

Investigations  and  Reports  Made  After  the  1900  Failure  53 

The   Johnson    Contract    56 

APPENDIX  2 

CONTRACT  or  WILLIAM  D.  JOHNSON  AND  ASSIGNS  FOR  THE  RECONSTRUCTION  OF  AUSTIN  DAM 

AND  POWER  PLANT 

Franchise   Ordinance    57 

Indorsements   on   Ordinances 61 

Letter  Filed  with  City  61 

The  Contract  Specifications  61 

Abstract  of  Contract  Specifications  62 

Dam 62 

Excavation    62 

Grouting    63 

Cut-Off  Walls   63 

Supporting    Walls    63 

Old  Portions  of  Dam    63 

Gates   and    Appurtenances    63 

Sluice    Gates    63 

Core    Wall    63 

Track— Walk  and  Pipe  Line  63 

Reservoir    63 

Timber    64 

Cement    64 

Sand    64 

Stone  or  Gravel    64 

Structural  Steel  and  Steel  Reinforcement   64 

Forms  for  Concrete   64 

Proportion  of  Ingredients   64 

Mixing    64 

Placing  of  Concrete  64 

Power    House    64 

Head  Gates  and  Hoists  64 

Intakes    64 

Draft    Tubes    64 

Tail  Race    64 

Power  House  Equipment  64 

Pumps    64 

Transmission  Line    64 

Engineer    64 

Plans 66 

APPENDIX  3 

WORK  UNDER  JOHNSON  CONTRACT  OF  1911 — INCLUDING  CHANGES  IN   PLANS  PROGRESS  OF 
WORK  AND  DEVELOPMENT  OF  CONDITIONS 

First  Change  in  Plans  66 

Approval  of  Detailed  Plans  Including  Certain  Changes  66 

Progress  and  Character  of  Work  67 

Changes  Made  in  Rebuilding  the  Austin  Dam  74 


Table  of  Contents.  vii 

APPENDIX  4 

CONDITIONS  AND  FACTS  ASCERTAINED  DURING  EXAMINATION  BY  DANIEL  W.  MEAD, 

AUGUST,  1917 

Examination  of  August,  1917   76 

Memoranda  Concerning  the  Foundation  Conditions  of  the  Austin  Dam  from  Sketches 

and  Data  Furnished  by  Mr.  Frank  S.  Taylor  81 

General  Scheme  of  Tests    81 

Auxiliary  Holes  Under  and  Between  Diaphragm  Walls   86 

On  the  Down  Stream  Side  of  the  Old  Dam   86 

Abstract  of  Record  of  Drilling  Holes  and  Grouting  87 

Notes  Based  on  Information  Furnished  by  Mr.  S.  S.  Posey  92 

Cross  Walls    92 

Leakage    93 

Leak  under  the  Dam   94 

Seepage  in  the  Old  Dam 95 

Class  of  Work   95 

Cofferdams    96 

General  Amount  of  Pumping   96 

Grouting    96 

Concrete     96 

Reinforcing    96 

Power  House  Foundations 97 

Tail   Race    97 

Penstock  and  Draft  Tubes 97 

Conduct  of  the  Work   97 

Discussion  of  Conditions  Below  the  Toe  of  the  Present  Dam  98 

Relative  Elevations  of  Dam  Foundation  and  Rock  in  Front  of  Toe   105 

Geological  and  Physical  Conditions  at  the  Dam  Site  106 

APPENDIX  5 

DISCUSSION  AND  CRITICISMS  OF  THE  CONDITIONS  AND  STRUCTURES  OF  THE  PRESENT 

INSTALLATION 

Essential  Principles  for  the  Construction  of  Safe  Dams   115 

Grouting    118 

Deep  Seepage  Under  and  Around  the  Dam   120 

Flow  Data  of  Colorado  River  and  Barton  Creek   120 

The  Structure  of  the  Old  Dam    124 

Stability  of  the  Old  Section  under  Original  Conditions  124 

The  Use  of  the  Old  Section  for  the  New  Conditions 126 

For  No  Silt  and  Low  Water  Conditions   128 

For  Silt  and  Low  Water  Conditions   128 

For  Silt  with  a  Nine  Foot  Flood   129 

For  a  Maximum  Flood  without  Silt   129 

The  Reinforced  Concrete  Structure   130 

Foundation    Pressures    130 

Hollow  Dam   Section    133 

Design  of  Reinforced  Concrete  in  the  Reinforced  Concrete  Dam  Section  133 

Appurtenances    136 

Sluice  Gates   136 

Crest    Gates    139 

Tail   Race    139 

Passageway  in  Dam 139 

Railing  on  Dam    139 

Head   Gate  Masonry    139 

Head  Gate  Racks   140 

Head  Gate  Hoists  140 

Penstocks  and  Draft  Tubes  140 

Station   Equipment    140 

Transmission    Line    140 

Pumps    140 

Reservoir    143 

APPENDIX  6 
A  STUDY  OF  THE  STREAM  FLOW  OF  THE  COLORADO  RIVER  AND  THE  PROBABLE  AMOUNT  OF 

POWER   THAT  CAN   BE  DEVELOPED  AT  THE  AUSTIN   DAM — WlTH   A   COMPARISON    OF   THE   REL- 
ATIVE VALUES  OF  65  AND  60-FooT  HEADS 

Stream   Flow   Data    144 

Comparison  of  Published  Records  and  Those  Computed  for  Austin  Dam    145 

Reliability  of  Records    146 

Hydrographs  Based  on  the  Calculations  of  Stream  Flow  146 

Power  Possibilities  Determined  from  Hydrographs    146 

Storage  above  the  Dam   147 

Modification  of  Hydrographs  by  Storage 147 


viii  Table  of  Contents. 

Deductions  from  the  Flow  at  the  Congress  Avenue  Bridge  147 

Graphical  Representation    148 

Power  Demand    148 

Power   Calculations    148 

Study  of  Minimum  Power  of  830  Horse  Power  or  600,000  Horse  Power  Hours  per 

Month    of    30    Days    148 

Study  of  the  Development  of  1650  Continuous  Horse  Power  157 

Development  of  1650  Horse  Power  under  65-Foot  Head   157 

Development  of  1650  Horse  Power  under  60-Foot  Head   157 

Comparison  of  65  and   60-Foot  Heads  for  the  Development  of   1650   Continuous 

Horse   Power    157 

Study  of  the  Development  of  3300  Continuous  Horse  Power  158 

Development  of  3300  Horse  Power  under  65-Foot  Head   158 

Development  of  3300  Horse  Power  under  60-Foot  Head  158 

Comparison  of  65  and  60-Foot  Heads  for  the  Development  of  3300  Continuous  Horse 

Power   < 158 

Effect   of   Smaller   Storage    172 

Reduction  of  Evaporation  and  Seepage  172 

Variations  in  Load   172 

APPENDIX  7 
CREST  GATES  FOB  THE  AUSTIN  DAM 

Conditions  of   Installation    173 

Types  of  Gates  Available  174 

APPENDIX  8 
BETTERMENTS  REQUIRED  FOR  THE  SAFETY  OF  THE  AUSTIN  DAM 

General    179 

Foundation    180 

Grouting  as  a  Protection  against  Underflow   180 

Foundation  Betterments  Recommended    180 

Stopping  Leaks  in  Panels  4  and  6  181 

Effectiveness  of  Protection   181 

Improvements  of  Conditions  Below  Toe  of  Dam   182 

Crest   Gates    182 

Reduction  in  Seepage  around  Dam   182 

Improvements  to  Old  Dam  Section  183 

Tail  Race    184 

Deflecting  Wall   184 

Head   Gates    184 

Passageway  in  Dam   185 

Railing    185 

Gate  Operating  Mechanism    185 

Sluiceways 185 

Sluice  Gates   185 

Estimates  of  Cost  of  Betterments  185 

APPENDIX  9 
COST  OF  WORK  DONE  UNDER  THE  JOHNSON  CONTRACT 

Estimated   Cost  of  Reservoir    187 

Estimated  Cost  of  Rebuilding  Station  Including  Removing  Old  Penstocks,  Placing 

New  Penstocks,  Rebuilding  Transmission  Line    188 

Machinery  and  Equipment   190 

Construction  of  the  Dam   190 

Extra    Work    192 

Recapitulation   of   Estimates    193 

Contractor's  Cost  of  Constructing  Reservoir  194 

Contractor's   Cost,   Schedule  A    195 

Contractor's  Cost,  Schedule  B   195 

Contractor's  Cost  of  Reconstruction  of  Dam   196 

Contractor's  Cost  of  Extras 196 

Austin  Dam  Costs  to  March  1,  1916   198 

APPENDIX  10 
Recommendations  of  Dr.  A.  C.  Scott,  March  31,  1915  199 

APPENDIX  11 
Bibliography  of  the  Austin  (Texas)  Dam  202 


LETTER  OF  TRANSMITTAL 

HONORABLE  A.  P.  WOOLDRIDGE,  Mayor, 
HONORABLE  E.  C.  BARTHOLOMEW,  Supt., 

Parks  and  Public  Property, 
Austin,  Texas. 

GENTLEMEN  :  In  accordance  with  the  instructions  contained  in  a  certain  resolu- 
tion adopted  May  30,  1917,  by  the  City  Council  of  Austin,  and  certain  written  and 
verbal  instructions  received  from  you,  I  have  made  an  examination  of  the  work,  ma- 
terial and  machinery  furnished  and  installed  under  a  contract  made  between  the  City 
of  Austin  and  William  D.  Johnson  and  assigns,  dated  September  22,  1911. 

I  have  also  investigated  the  physical  conditions  surrounding  this  installation, 
and  in  accordance  with  instructions  I  submit  herewith  my  report. 

In  order  to  present  this  matter  fully,  I  have  found  it  essential  to  describe  some- 
what briefly  the  history  of  the  Austin  dam  and  the  conditions  leading  up  to  its  de- 
struction in  1900.  I  have  also  endeavored  to  explain  the  conditions  and  the  engi- 
neering principles  on  which  the  successful  consummation  of  this  project  must  rest, 
in  as  simple  and  plain  a  manner  as  possible,  in  order  that  the  citizens  of  Austin  may 
understand  the  defects  found  and  the  betterments  needed  to  put  the  installation 
into  safe  condition.  I  have  also  endeavored  to  give  the  technical  information  on 
which  my  opinions  rest,  in  sufficient  detail  that  my  findings  may,  if  you  desire,  be 
reviewed  and  checked  by  other  engineers  without  the  further  expense  of  elaborate 
investigations  and  calculations. 

It  should  be  understood  that  the  work  on  the  dam  was  supposed  to  be  practi- 
cally complete  in  1915,  until  floods  developed  certain  weaknesses  in  the  structures 
and  until  certain  changes  in  plans,  not  understood  by  the  City  Council,  were  discov- 
ered. At  the  time  of  my  examination  the  foundations  were  under  water  and  could 
not  be  examined  in  detail  at  any  permissible  expense;  the  conditions  leading  up  to 
the  contract  and  the  events  of  construction  were  matters  of  history  which  could  not 
be  ascertained  except  from  the  statements  of  those  familiar  with  them ;  the  available 
plans  on  which  the  work  was  done  were  not  entirely  complete  and  apparently  had 
not  been  corrected  for  possible  construction  changes;  and  I  have  in  consequence 
been  obliged  to  depend  on  individual  statements,  more  or  less  official  records  and 
published  articles  in  the  technical  press,  as  well  as  on  my  personal  examination. 
Various  photographs,  maps  and  sketches  have  been  included  in  the  report  in  order 


2  ^Report  on  the  Dam  at  Austin,  Texas. 

to  make  clear  many  conditions  which  cannot  well  be  understood  from  a  written  de- 

scription. 

It  has  been  my  endeavor  to  investigate  this  project  as  fully  and  accurately  as 
its  importance  demands,  and  to  make  my  report  comprehensive,  accurate,  simpl< 

and  fair  to  all  concerned. 

Very  respectfully, 

TTP-.          .  DANIEL  W.  MEAD. 

Madison,  Wisconsin. 

November  20,  1917. 


INSTRUCTIONS 

The  instructions  on  which  the  report  is  based  were  contained  in  the  following 
resolution : 

RESOLUTION 

Resolved,  by  the  City  Council  of  the  City  of  Austin,  Texas :  That  the  Mayor  and 
Superintendent  of  Parks  and  Public  Property  of  this  City  be  and  hereby  are  author- 
ized jointly  to  engage  the  professional  services  of  some  engineer  of  high  character 
and  of  exceptional  ability  and  experience  in  such  work  to  carefully  examine,  upon 
the  ground  and  otherwise,  into  the  whole  physical  situation  at  the  dam  and  power 
house  and  advise  this  City  as  to  the  character  and  conditions  of  these  structures  and 
report  fully  upon  the  work  done  in  the  rebuilding  of  the  dam,  and 

Be  it  Further  Resolved:  That  amongst  the  matters  to  be  especially  referred  to 
such  engineer  for  investigation  and  report  shall  be  the  determination  as  to  whether 
or  not  the  dam,  as  rebuilt,  is  rebuilt  in  compliance  with  the  plans  and  specifications 
provided  by  the  City  of  Austin  for  this  structure,  and  if  there  are  any  variations 
from  the  original  plans  and  specifications,  what  they  are,  and  what  are  their  effect 
upon  the  dam,  and  he  is  especially  instructed  to  investigate  and  report  as  to  the  ef- 
fect upon  the  stability  of  the  dam  of  the  narrowing  of  its  base  from  the  width  of  the 
base  as  originally  prescribed  in  the  original  plans  and  specifications  for  the  re- 
building of  the  dam,  and 

i  ~ 

Be  it  Further  Resolved:  That  he  shall  be  instructed  to  ascertain  what  defects,  if 
any,  exist  in  the  dam  and  how  such  defects  may  be  remedied,  and  he  is  especially 
enjoined  to  investigate  and  advise  as  to  what  things  should  be  reasonably  done  to 
give  the  dam  the  greatest  practicable  stability  and  safety,  and 

Be  it  Further  Resolved:  That  he  be  instructed  to  pass  upon  the  efficiency  of  said 
dam  and  its  permanency  as  to  structure  for  all  probable  time  and  suggest  such  ad- 
ditional things,  if  any,  proper  to  be  done  to  make  such  structure  permanently  stable 
and  efficient,  and 

Be  it  Further  Resolved:  That  he  is  hereby  instructed  to  estimate  the  cost  of 
such  changes,  improvements,  betterments  and  additions  to  and  at  the  dam  as  he  may 
deem  proper  to  recommend  to  the  consideration  of  the  City  Council,  and 

Be  it  Further  Resolved:  That  he  is  hereby  especially  instructed  to  estimate  the 
value  of  the  material  and  labor  put  into  the  dam  by  the  present  contractors  and 
builders,  and  the  value  of  the  work  done  in  and  at  the  power  house,  and  the  value  of 
the  reservoir,  and  the  value  of  the  equipment  at  the  power  house ;  such  information 
to  be  of  such  use  to  the  City  Council  as  it  may  find  occasion  to  make  of  the  same,  and 


4  Report  on  the  Darn  at  Austin,  Texas. 

Be  it  Further  Resolved:  That  said  engineer  be  instructed  to  do  all  reasonably 
necessary  and  proper  things  to  inform  the  public  upon  the  dam;  First,  as  to  its 
stability;  and  second,  as  to  its  efficiency,  so  that  in  the  event  the  City  should  either 
desire  to  purchase  the  dam  and  its  appurtenance  properties  outright,  or  to  insist 
upon  the  execution  of  the  present  contract,  with  or  without  modification,  it  may  have 
the  full  and  intelligent  facts  before  it  upon  which  to  base  its  future  action,  and 

Be  it  Further  and  Finally  Resolved:  That  the  employment  of  an  engineer  shall 
not  in  any  way  modify,  or  waive  any  provision  or  obligation  contained  in  the  con- 
tract made  by  the  City  of  Austin  with  Wm.  D.  Johnson  and  his  assigns  for  rebuild- 
ing the  dam  across  the  Colorado  Eiver  above  the  City  of  Austin. 

Adopted:     May  30th,  1917. 
Yeas :     5 
Approved:    May  30th,  1917, 

A.  P.  WOOLDKIDGE, 

Mayor. 

To  the  instructions  contained  in  the  above  resolution  were  added  further  instruc- 
tions contained  in  a  letter  from  the  Hon.  A.  P.  Wooldridge,  Mayor,  dated  Septem- 
ber 14,  1917,  as  follows: 

"If  you  consider  there  are  important  additions  to  be  made  to  the  dam  to 
assure  its  stability,  you  will  separate  such  additional  work  as  may  be  called  for, 
or  fairly  implied  in  the  terms  of  the  present  contract,  from  those  which  ought 
to  be  done  but  yet  are  not  set  out  in  the  present  contract,  nor  fairly  deducible 
from  its  provisions.  *  *  *  In  other  words,  to  make  myself  clear :  If  there  are, 
in  your  judgment,  any  additional  things  which  ought  to  be  done  to  assure  the 
stability  of  the  dam  as  it  now  stands,  you  will  please  say  so,  stating  if  the  cost  of 
these  additional  things  properly  devolve  upon  the  Contractors  or  upon  the 
City." 


ACKNOWLEDGMENTS 

The  writer  desires  to  acknowledge  the  valuable  assistance  and  information  fur- 
nished him  during  his  investigation  by  Hon.  A.  P.  Wooldridge,  Mayor;  Hon.  E.  C. 
Bartholomew,  Superintendent  of  Parks  and  Public  Property ;  Mr.  Guy  A.  Collett,  Re- 
ceiver,  and  Dr.  S.  W.  Simonds  of  the  University  of  Texas ;  also  from  Mr.  Frank  S. 
Taylor,  Resident  Engineer,  who  furnished  numerous  plans,  specifications,  data  and 
explanations,  not  otherwise  available ;  also  to  Mr.  S.  S.  Posey,  Inspecting  Engineer 
for  the  City,  who  was  present  during  essentially  the  entire  construction  period  and 
who  accompanied  the  writer  during  his  entire  examination;  also  to  Mr.  H.  L.  Cobb, 
Assistant  Engineer  of  Construction,  for  various  information  and  for  many  photo- 
graphs taken  during  construction  and  showing  conditions  otherwise  unascertain- 
able ;  also  to  Mr.  W.  P.  Johnson,  Engineer  of  the  City  Power  Station ;  and  to  Mr. 
Miller  who  is  now  in  charge  at  the  dam  for  the  Receiver.  Various  information  has 
been  secured  from  the  technical  press  and  from  other  sources  which  the  writer  has 
endeavored  to  acknowledge  in  the  report. 


REPORT  ON 

THE  WATER  POWER  DEVELOPMENT 

AT  AUSTIN,  TEXAS 

The  original  Austin  dam,  built  across  the  Colorado  Eiver  near  Austin,  Texas, 
and  completed  in  1893,  was  the  consummation  of  a  local  ideal  that  had  existed  more 
than  fifty  years. 

The  City  of  Austin,  with  a  population  of  less  than  15,000,  undertook  a  daring 
venture  when  it  expended  about  $1,600,000  for  electric  light  and  water  works,  and 
the  construction  of  the  greatest  overflow  dam  that  had  then  been  built  across  a  large 
and  torrential  stream.  The  failure  of  the  venture  in  1900,  due  largely  to  the  engi- 
neering and  administrative  inexperience  of  the  time,  was  a  serious  blow  to  that  pro- 
gressive City. 

After  its  unfortunate  experience,  the  City  did  not  desire  to  reconstruct  this  dam 
by  direct  taxation  but  elected  to  make  a  contract  whereby  the  work  of  reconstruc- 
tion, rehabilitation  and  maintenance,  and  the  risk  involved,  were  to  be  assumed  by 
a  private  company.  This  company  was  to  be  reimbursed  for  its  expense  and  re- 
warded for  its  endeavors  by  a  payment  of  $100,000  in  cash  on  the  completion  and 
acceptance  of  the  work,  and  by  semi-annual  payments  of  $32,400  each  for  twenty- 
five  years  to  be  derived  from  the  income  of  the  plants  which  utilized  the  power  so 
developed.  On  this  basis  the  City  entered  into  a  contract  in  1911  with  Mr.  Win.  D. 
Johnson  for  the  reconstruction  of  the  dam,  power  station  and  accessories. 

METHOD  OF  FINANCING 

Although  the  method  used  for  financing  the  reconstruction  of  the  Austin  dam  is 
a  common  one  for  promotive  enterprises,  it  is  an  unfortunate  method  to  be  used  in 
connection  with  the  construction  of  municipal  public  works.  For  any  enterprise  this 
method  of  financing  is  an  exceedingly  extravagant  one,  and  its  general  tendency  is 
toward  cheap  and  faulty  construction  or  exceedingly  high  costs,  or  both.  Usually  a 
company  is  organized  for  the  purposes  of  promotion  is  financially  irresponsible  be- 
cause its  capital  stock  commonly  represents  only  anticipated  profits.  Bonds  are  usu- 
ally issued  to  meet  the  entire  promoting,  financial  and  construction  expenses,  and 
these  bonds,  on  account  of  the  nature  of  such  enterprises  and  the  risks  involved, 
must  commonly  be  sold  to  bond  brokers  at  a  heavy  discount.  The  work  is  com- 
monly let  to  contractors,  who  in  their  turn  should  receive  an  adequate  profit.  In 
such  an  enterprise  therefore  the  profit  of  the  Bond  Dealer,  and  the  profit  of  the 
Promoter  must  be  included  in  the  cost  price  of  the  work. 

The  total  expense  to  the  City  of  Austin,  involved  by  the  franchise  during  the 
25-year  period,  was  $1,720,000,  with  a  present  cash  value  of  approximately  one  mil- 
lion dollars.  The  City  Water  Works  Company,  the  promoting  company  organized 


8  Report  on  the  Dam  at  Austin,  Texas. 

to  finance  the  endeavor,  arranged  for  an  issue  of  $750,000  which  it  contracted  to  sell 
at  75  per  cent,  of  its  face  value.  Its  contract  with  the  Wm.  P.  Carmichael  Company 
of  St.  Louis,  provided  for  the  maximum  cost  of  the  work  to  be  done  at  $453,000, 
which  sum  was  to  include  $50,000  profit  to  that  Company.  The  scheme  therefore 
stood  as  follows : 

Promoters'  Expense  and  Profit $250,000 

Discount  to  pay  Expenses  and  Profit  on  Sale  of  Bonds 187,500 

Contractor's  Profit  50,000 

Estimated  Maximum  Cost  of  Work 403,000 


Total    $890,500 

Leaving  for  Contingent  Expenses  and  Extra  Profit  for  Promo- 
tion           109,500 


Cost  to  the  City $1,000,000 

Thus  it  was  proposed  by  the  Promoters  to  construct  an  adequate  plant  for 
$1,000,000,  of  which  only  $453,000  was  to  be  paid  to  the  Contractor  for  the  actual  cost 
of  the  completed  work  and  the  Contractor's  profit;  and  $547,000  was  to  be  used  for 
financial  and  promotive  expenses  and  Promoters'  profit. 

There  is  nothing  necessarily  illegal  or  inequitable  in  such  a  financial  plan,  pro- 
vided the  plan  is  fully  understood,  the  financing  is  on  an  adequate  basis,  the  bonds 
are  sold  to  purchasers  who  understand  the  risk  involved,  and  the  work  is  honestly, 
intelligently  and  adequately  done.  The  objections  to  it  are : 

1st.  The  lack  of  real  responsibility  on  the  part  of  the  promoters. 

2d.  The  tendency  to  false  economy  to  assure  or  to  inflate  profit. 

3d.  The  temptation  to  give  false  assurances  to  purchasers  as  to  the  safety 
of  the  securities  sold. 

4th.  The  large  expense  involved  compared  with  the  actual  cost  of  the  work 
to  be  done. 

It  is  recognized  by  all  familiar  with  the  construction  of  large  enterprises  that 
there  is  no  other  method  by  which  work  is  financed  that  requires  closer  scrutiny  of 
the  personnel  and  experience  of  the  promoters  and  their  engineers,  of  the  financial 
and  construction  plans,  and  of  the  contract  and  specifications  in  order  to  assure  hon- 
est, conscientious  and  proper  work,  and  a  successful  outcome  of  the  endeavor.  Such 
scrutiny  is  necessary  on  account  of  the  fact  that  unless  the  endeavor  is  so  success- 
ful that  the  promoters  will  have  a  considerable  equity  remaining  in  the  work  after 
construction  and  acceptance,  they  will  abandon  the  enterprise  leaving  the  unorgan- 
ized innocent  purchasers  of  securities,  and  their  creditors,  as  the  only  parties  who 
have  an  actual  financial  interest  in  the  uncompleted  or  unsuccessful  endeavor,  as  has 
actually  occurred  in  the  case  at  hand. 


The  Reconstruction  Work. 


PLANS  AND  SPECIFICATIONS 

The  plans  and  specifications  which  were  the  basis  of  the  contract  were  of  the 
most  general  character  and  not  sufficient  to  afford  a  basis  for  a  professional  opinion 
as  to  their  adequacy,  without  numerous  assumptions  as  to  essential  matters  which 
were  not  shown  or  explained  in  detail.  The  City  did  not  secure  independent  expert 
advice  concerning  the  plans  proposed,  but  a  special  effort  was  made  in  the  franchise 
ordinance,  which  constituted  the  contract  under  which  the  work  was  done,  to  bind  the 
promoter  and  his  assigns  as  to  the  progress  of  the  work,  time  of  completion,  com- 
pleteness of  equipment,  capacity  of  equipment,  maintenance  of  structures,  and  for 
the  minimum  power. 

The  general  plans  and  specifications  accepted  and  made  a  part  of  the  contract 
were  to  be  followed  by  detailed  plans  and  specifications,  but  all  plans  were  subject 
to  any  change  that  the  engineers  of  the  promoter  might  desire,  limited  only  by  the 
following  provision: 

"Provided,  such  changes  do  not  decrease  the  amount  of  equipment  in  the 
power  house,  the  height  or  stability  of  the  dam,  the  size  of  the  reservoir,  or  in 
any  way  diminish  the  capacity  or  completeness  of  the  installation,  or  in  any  way 
lower  the  standard  or  grade  of  construction." 

THE  EECONSTRUCTION  WORK 

In  order  to  satisfy  the  contract  requirements  and  to  maintain  the  rate  of  pro- 
gress specified,  work  was  begun  on  the  power  station  in  the  fall  of  1911  by  the  City 
Water  Power  Company  by  day  work.  A  contract  was,  however,  entered  into  on 
June  1,  1912,  between  the  Company  and  The  William  P.  Carmichael  Company  to  as- 
sume the  expense  of  the  work  already  done  and  to  complete  the  entire  work  involved 
in  the  contract. 

The  contractor  endeavored  to  protect  itself  by  a  provision  in  the  contract '  *  that 
said  Company  (the  City  Water  Power  Company)  is  solely  responsible  for  the  suffi- 
ciency and  correctness  of  said  plans,  specifications  and  designs."  This  provision 
would  have  been  sufficient  for  the  protection  intended  if  the  contract  had  been  made 
with  a  responsible  or  with  a  successful  company,  but  was  without  avail  under  the 
actual  conditions  which  afterward  obtained. 

THE  CONTRACTOR  FOR  THE  WORK 

The  William  P.  Carmichael  Company  had  constructed  the  Congress  A  venue  rein- 
forced concrete  arch  bridge  at  Austin,  and  had  had  extensive  experience  in  con- 
crete work,  but  apparently  little  experience  with  river  work.  The  work  at  Congress 
Street  had  practically  been  done  during  the  year  1909,  during  which  year  the  mean 
annual  and  the  maximum  and  minimum  flows  of  the  Colorado  were  near  the  min- 
imum (see  Fig  1).  They  began  work  on  this  project  during  1912,  which  year  had 


10 


Report  on  the  Dam  at  Austin,  Texas. 


the  lowest  mean  flow  on  record ;  but  unfortunately  they  were  obliged  to  confine  their 
attention  largely  to  construction  outside  of  the  channel,  and  the  advantages  of  this 
period  of  exceptional  low  water  were  lost.  The  work  of  construction  in  the  chan- 


Mtnimum  Mean  MotifMy  ffotv. 
Maximum  Me&n  Monfh/u  F/ow. 


W7 


FIGURE  1 — Mean  Annual,  Minimum   Mean  Monthly  and  Maximum  Mean  Monthly  Flow  of 

Colorado  River  at  Austin,  Texas. 

nel  was  performed  during  the  years  1913  and  1914,  during  which  the  mean  annual  and 
the  maximum  mean  monthly  flows  of  the  river  were  the  largest  of  any  years  of  record 
except  the  year  1900.  The  results  of  inexperience  with  river  work  and  the  unfor- 
tunate conditions  of  flow  were  all  that  could  be  expected.  The  frequent  destruction 
of  cofferdams  and  the  work  already  completed,  the  extra  expense  involved  by  delays, 
and  other  unforeseen  contingencies  of  river  work  added  materially  to  the  expense  of 
the  work. 


The  Reconstruction  Work.  1 1 

It  was  found  necessary  to  add  to  the  anticipated  work  on  the  power  station,  pen- 
stocks, station  equipment,  etc.,  and  the  Contractor  presented  a  bill  of  extras 
amounting  to  about  $109,500,  making  the  total  claims  for  work  done  $563,500  which, 
however,  was  insufficient  to  make  good  the  cost,  for  the  books  of  the  Contractor 
show  a  total  construction  cost  of  $795,332.19,  involving  a  construction  loss  of 
$251,465.70,  if  the  entire  amount  apparently  due  is  ultimately  collected. 

THE  BOND  ISSUE 

The  bonds  issued  by  the  City  Power  Company  were  underwritten  by  Lawrence 
Barnham  and  Company  of  New  York  at  75  per  cent.,  and  $412,500  par  value  in 
bonds  has  been  taken  by  the  underwriters.  It  is  understood  that  most  of  these  bonds 
are  in  the  hands  of  individual  purchasers  who  took  them  on  approximately  a  98  per 
cent,  basis.  The  balance  of  the  bonds,  amounting  to  $337,500,  are  held  by  the  New 
York  Trust  Company,  Trustees. 

WOEK  APPARENTLY  NEARING  COMPLETION 

In  the  spring  of  1915  the  work  was  apparently  nearing  completion.  The  water 
reached  the  level  of  the  crest  of  the  old  dam  on  February  16, 1915,  for  the  first  time 
since  its  destruction  in  1900.  The  gates  were  found  to  leak  badly  and  stanching 
strips  were  added  to  tighten  them.  The  turbines  and  equipment  were  tested  in 
March  and  declared  satisfactory.  March  31,  the  Engineer  of  the  City  presented  a 
statement  of  those  things  which  he  considered  necessary  to  complete  the  contract 
ready  for  the  acceptance  of  the  work.  (See  Appendix  10.)  Early  in  April,  the 
City,  regarding  the  work  as  nearly  completed,  advanced  $21,000  to  assure  immed- 
iate completion. 

DIFFICULTIES  ARISE 

The  Wm.  P.  Carmichael  Company  was  to  be  paid  $250,000  by  the  City  Water 
Power  Company  as  soon  as  that  value  in  work  had  been  done  under  the  contract, 
and  was  to  receive  no  further  payment  until  the  work  was  completed  and  accepted. 
The  first  payment  was  duly  made;  the  unexpected  extra  expense,  however,  embar- 
rassed the  Contractor  and  exhausted  its  resources.  The  City  Water  Power  Com- 
pany was  unable  to  advance  further  funds  until  the  work  was  accepted  and  further 
bonds  could  be  sold. 

On  April  20,  1915,  a  retaining  wall  next  to  the  power  house  went  out  for  the 
second  time.  On  April  23,  a  flood  carried  out  four  of  the  automatic  crest  gates  and 
practically  filled  up  the  tail  race.  The  gates  were  replaced  and  the  tail  race 
cleaned  out. 

The  roofs  of  some  of  the  sluice  conduits  were  destroyed  when  the  sluice  gates 
were  opened.  These  had  to  be  replaced  and  strengthened. 


1 2  Report  on  the  Dam  at  Austin,  Texas. 

The  City  naturally  refused  acceptance  until  these  various  defects  were  rem- 
edied. The  bond  holders  advanced  about  $11,000  to  assure  the  completion  of  the 
work.  Certain  changes  in  the  plans,  unknown  to  the  City  Council,  were  discovered 
and  their  validity  was  questioned.  Two  leaks  were  discovered  under  the  new  por- 
tion of  the  dam.  A  greater  flood  in  September  (see  Frontispiece)  carried  away 
most  of  the  gates  and  again  filled  the  tail  race. 

FINANCIAL  COLLAPSE 

As  the  defects  became  more  apparent,  the  possibility  of  securing  an  acceptance 
from  the  City  became  more  remote.  The  funds  available  were  too  small  to  complete 
the  repairs  which  evidently  were  needed.  The  Contractor  had  apparently  exhausted 
every  resource  and  was  obliged  to  assign. 

The  Contractor  had  filed  a  mechanic's  lien  on  the  property  for  the  balance 
claimed  as  still  due  ($270,983.79).  The  Engineers  of  the  City  Water  Power  Com- 
pany filed  liens  to  approximately  $24,200  in  addition  to  a  judgment  previously  se- 
cured against  the  Company  for  about  $1800.  Bonds  amounting  to  $412,500  were 
outstanding.  The  apparent  claim  against  the  franchise  and  property  at  the  present 
time  is  therefore  $709,483.79. 

The  City  Water  Power  Company  was  deeply  involved  and  without  resource. 
The  officials  apparently  lost  interest  and  neglected  or  abandoned  the  work,  and  by 
mutual  agreement  of  all  interested  parties  the  Federal  Court  appointed  Mr.  Guy  A. 
Collett  as  Receiver  for  the  property. 

PERIOD  OF  INVESTIGATION 

For  two  years  practically  nothing  has  been  done  toward  completing  the  plant. 
Brief  examinations  have  been  made  and  preliminary  reports  rendered  by  various  en- 
gineers for  several  interested  parties  with  the  hope  that  in  some  way  the  defects 
could  be  remedied  so  that  the  installation  would  be  accepted  by  the  City  and  the 
interests  adjusted.  The  City,  feeling  that  no  prerequisites  for  acceptance  could  be 
specified  without  a  detailed  knowledge  of  the  defects,  decided  to  investigate  the  en- 
tire matter. 

This  report  is  made  to  afford  full  information  to  the  citizens  of  Austin,  and  as 
a  basis  of  action  for  the  City  Council  in  accordance  with  the  resolution  of  May  30, 
1917,  that  ' '  it  may  have  the  full  and  intelligent  facts  before  it  upon  which  to  base  its 
future  action." 

PHYSICAL  CONDITIONS  AT  THE  DAM  SITE 

The  original  dam  and  the  structure  built  under  the  Johnson  franchise  were 
built  across  the  canyon  of  the  Colorado  River  about  three  miles  from  the  center  of 
the  City  of  Austin.  The  entire  location  is  within  the  Balcones  fault  zone  (see 
Fig.  2,  page  13),  and  the  entire  foundation  is  on  the  Edward's  limestone  forma- 


Physical  Conditions  at  the  Dam  Site. 


13 


FIGUBE  2— Map  Showing  Fault  Lines  of  Balcones  Fault  Zone  Near  Austin,  Texas.     (From  Aus- 
tin Folio,  U.  S.  Geol.  Survey) 


14 


Report  on  the  Dam  at  Austin,  Texas. 


tion  which  has  undergone  a  downward  displacement  of  many  feet  (see  Fig.  3, 
page  14).  The  formations  in  the  river  bed  at  the  dam  site  are  jointed  and  faulted, 
the  main  fault  planes  undoubtedly  extending  deep  below  the  river  bed.  On  the  east 
side  of  the  site  there  is  apparently  a  block  fault  in  which  the  strata  have  been  broken 
and  shattered,  and  much  of  the  original  lime  has  been  leached  out  by  percolating 
waters,  leaving  clay  seams  and  voids  in  the  strata.  The  physical  conditions  have 
been  described  in  some  detail  in  Appendices  1  and  4  to  which  reference  should  be 
made  for  a  more  detailed  description. 


\    \ 

Fee 

loo 

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Austin  chalk. 

1    I 

1    1 

!,  1 

Buda(MoaiCre*tflunt3l»a* 

Del  fio  cloys 

Fort  Worth  ifmestonc. 

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i 

sT.-v.r. 

M 

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Cama.-K/>c.fbo*/im*ftfne 

f    J    1 
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G/tJi  Rax  format  fen 

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1       1 

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Travis  Fkak  formation 

^yvi:;' 

tySr 

-  Eagle,  forctihatxj 


FIGURE  3 — Section  Along  West  Side  of  Colorado  River  at  Austin,  Texas,  Showing  Local  Fault  of 
Balcones    Fault    Zone    (Austin  Folio,  U.  S.  Geol.  Survey) 

THE  OLD  DAM 

The  solid  structure  of  the  original  dam,  finished  in  1893,  apparently  furnished 
by  its  width  of  base  a  sufficient  resistance  to  underflow  so  that  it  stood  for  some  years. 
Various  leaks  developed,  however,  near  the  east  end  of  the  structure,  especially  un- 
der the  head  gates,  and  were  repaired  in  an  imperfect  way.  One  of  these  caused  con- 
siderable damage  before  the  completion  of  the  power  house.  (See  Appendix,  page 
46,  Fig.  17.)  In  1900  the  east  half  of  the  original  dam  over  the  badly  faulted  area 
failed,  due  to  the  erosion  of  the  rock  below  its  toe,  the  undermining  of  the  toe,  and 
possibly  to  the  development  of  leaks  under  its  foundation. 

THE  NEW  STRUCTURE 

The  structure  built  under  the  Johnson  contract  consisted  of  a  reinforced  con- 
crete section  built  in  the  opening  where  the  previous  dam  had  been  destroyed.  (See 
Fig.  4.)  Most  of  the  old  structure  remaining  was  utilized  practically  as  it  stood  and 
without  material  betterments. 

Work  on  the  power  house  and  reservoir  was  apparently  immediately  pushed  to 
completion,  and  operations  in  the  river  work  were  postponed  until  the  years  1913- 
14,  thus  losing  the  advantage  of  the  lowest  average  river  stages  experienced  on  the 
Colorado  in  twenty  years  of  record  and  bringing  the  construction  period  into  two  of 
the  heaviest  years  of  flow  on  record.  (See  Fig.  1,  page  10.) 


Changes   in  Plans. 


15 


PLANS  AND  SPECIFICATIONS 

The  specifications  (see  Appendix,  pages  61  to  65)  and  plans  (see  Appendix,  page 
65)  for  the  work,  submitted  with  the  franchise  and  made  a  part  thereof,  were  of  the 
most  general  character.  Conditions  were  further  complicated  by  the  right  received 
under  the  specifications  whereby  the  engineers  of  the  City  Water  Company  were  em- 
powered to  make  any  changes  they  desired,  provided  the  stability,  capacity,  com- 
pleteness or  grade  of  construction  were  not  reduced.  (See  page  9.)  Even  these 
limiting  conditions  were  restricted  by  the  requirement  that  any  difference  of  opin- 
ion between  the  Engineers  of  the  City  and  of  the  Company  must  be  arbitrated,  a 
process  so  cumbersome  that  it  seems  to  have  been  waived  in  every  case.  The  En- 
gineers of  the  City  could  only  inspect  and  suggest,  and  were  practically  powerless 
to  initiate  betterments  or  to  resist  more  than  radical  defects  or  changes.  Detailed 


K 47O' >K S6O'- - - >  0'       50'     100' 

UPSTREAM  ^-Concrete  CvMT  Wall  u  *t /  J  "  "  '  "  "  ' — 

-*=  *&'*      Oriqina/ 


200' 


0>d  Masonry    CtsrofT  Yto// 


-i  ;_if ;  T-.T  .  .T;xt  fc.  'fJ^c. 


0/cf  Masonry     CtsfofF  Wall 


Origr/naf  Masonry  Derm >K Hew  Spit/way  Section- 

Floor,  El. /75J> £niranc&.j<  sCrest-^pf  New  Spillway 


'•Crest  of  Prigrincrl 'Spit/way 
*        ^        ' 


Bottom' of  Concrete 

CuMFWd/f 


Line  of  SiH- below  Dam 


fitter  Line  as  shown  ty  > 
Orfgriner/Ar/ngs    ' 


FIGURE  4 — Plan  and  Elevation  of  the  Reconstruction  of  the  Austin  Dam  under  the  Con- 
tract with  William  D.  Johnson,   (from  Eng.  News  June  3,  1915.) 

plans  and  specifications  were  to  be  furnished  before  work  was  begun.  The  City, 
however,  never  received  a  complete  set  of  plans  but  in  lieu  of  this  the  Resident  En- 
gineer furnished  copies  of  the  principal  detailed  drawings,  with  a  list  of  other  draw- 
ings made,  and  an  offer  to  furnish  such  as  the  City  might  desire.  The  City  on  its 
part  made  no  demands  for  complete  details  and  has  only  an  incomplete  plan  of  the 
work  on  file. 

CHANGES  IN  PLANS 

The  original  reinforced  concrete  structure  (see  A.  Fig.  5,  page  17)  had 
diagonal  cross  walls,  spaced  24-foot  centers,  and  on  the  basis  of  the  scale  of  the 
drawing  was  deficient  in  strength.  On  Nov.  28,  1911,  this  plan,  with  the  approval 
of  the  City's  Engineer  and  the  City  Council,  was  changed  to  a  type  having  cross 
walls  normal  to  the  axis  of  the  dam  (see  B.  Fig.  5,  page  17),  and  spaced  20- 
foot  centers,  and  with  the  interval  of  the  crest  piers  increased.  Both  of  these  changes 
were  improvements  but  the  plan  still  remained  indefinite  in  detail  and  defective  in 
strength. 

In  May,  1912,  more  detailed  plans  were  submitted  on  which  much  more  definite 
information  was  given.  These  plans  were  'submitted  to  the  City's  Engineer  who 


16  Report  on  the  Dam  at  Austin,  Texas. 

after  an  examination  approved  them  but  failed  to  call  the  attention  of  the  City  offi- 
cials to  a  radical  change  in  width,  which  change  he  evidently  did  not  interpret  as  a 
change  in  stability,  capacity,  completeness  or  grade  of  construction. 

The  original  design  and  the  plans  substituted  in  November,  1911  called  for  a 
dam  with  a  width  parallel  to  the  stream  of  125'9".  The  detailed  plans  of  May,  1912 
(see  C,  Fig.  5,  page  17),  provided  for  a  base  width  of  93  feet.  The  new  plans 
also  called  for  additional  thickness  in  the  decks  of  the  structure  and  gave  the 
reinforcement  in  detail,  and  altogether  was  a  better  and  stronger  structure  than  in- 
dicated by  either  of  the  previous  plans. 

The  force  diagrams  (see  B,  Fig.  6,  page  18)  show  that  the  new  plan  repre- 
sents a  lighter  structure,  and  in  consequence  the  resultant  pressure  makes  a  less 
angle  with  the  base  line,  and  theoretically  the  dam  is  more  liable  to  slip  on  its  founda- 
tions or  on  any  underlying  clay  seams ;  but  the  improvements  in  other  ways  are  so 
marked  that  I  believe  the  change  in  width  is  of  practically  no  moment.  Various  other 
changes  in  details  were  made  some  of  which  were  material  betterments  and  others, 
including  the  change  in  width  of  dam,  were  undoubtedly  made  to  cheapen  construc- 
tion; others  were  forced  by  physical  conditions.  The  attention  of  the  City  Officials 
has  already  been  called  to  many  of  the  changes  made,  by  the  report  of  Mr.  S.  S. 
Posey  (see  C,  Fig.  6,  page  18). 

THE  EFFECTS  OF  CHANGES  IN  PLANS  AND  SPECIFICATIONS 

Betterments. — A  number  of  the  changes  made  were  distinct  betterments  to  the 
plans  as  originally  proposed.  Such  changes  are  as  follows: 

1.  Change  in  Type. — The  change  in  type  of  dam  from  diagonal  to  normal 
cross  walls  was  a  distinct  advantage  in  that  it  led  to  simplicity  of  design. 

2.  Change  in  Spacing  of  Walls. — The  reduction  in  the  spacing  of  cross  walls 
from  24  to  20  feet  was  a  distinct  betterment,  giving  a  greater  number  of  points 
of  support  to  the  decks  and  a  better  distribution  of  pressure  on  the  foundations. 

3.  Increase  in  Span  of  Crest  Gates. — The  original  plan  provides  crest  gates 
ten  feet  wide  for  the  new  section  and  eight  feet  wide  for  the  old  section.     These 
were  increased  to  eighteen  feet  in  width  for  both  sections.     This  was  an  improve- 
ment, and  with  stronger  gates  on  a  stream  carrying  little  drift  this  plan  might 
have  given  satisfactory  results. 

4.  Foot  Bridge  on  Dam. — The  original  plans  provided  for  a  wooden  struc- 
ture on  I-beam  supports  across  the  crest  of  the  dam.     This  was  changed  to  a 
reinforced  concrete  structure  in  order  to  carry  a  derrick  car  for  the  removal  of 
drift  and  for  the  manipulation  of  the  gates.     This  change  was  an  improvement. 

5.  Location  of  Sluice  Gates. — The  change  in  the  location  of  the  sluice  gates 
which  brought  these  gates  into  the  stream  channel  was  an  improvement. 


Changes   in  Plans. 


a.  /es.  o 


-PI an  and  Section  of  Com  as  Ortgina/ '/y  Proposed  -Sepf.  22 'CSf-  /$//. 


0  -  Section  of  Dam  as  Changed  and  fljo/y/wed  •  March  / 5  (2/3/2. 


C.   P/an  and  Section  of  Oam  as  Cfiangea"  and 
flpprovea/  rfay  /OH!  /9I2  anaf  as  Construe/fa"- 

FIGUBE  5 — Original  Plan  for  Reinforced  Concrete  Dam  at 
Austin,  Texas,  and  Successive  Changes  made  in  Same. 


*    a*    .ie>    ii*«.***>   *          *         «        **' 
•>»•'«     *   ,       «^r'J          «      ** 

Report  on  the  Dam  at  Austin,  Texas. 


FIGURE  6— Force  Diagrams  of  Original  and  Final  Sections  of  the  Austin  Dam. 


Changes  in  Plans.  19 

6.  Width  of  Cross  Walls. — The  base  width  of  the  cross  walls  was  shown  as 
one  foot  in  the  original  plans.     This  width  was  increased  to  2'6"  in  construction, 
which  was  a  change  for  the  better. 

7.  Thickness  of  Upstream  Deck. — The  thickness  of  the  upstream  deck  was 
increased  from  2'  to  2'6"  at  the  base,  and  from  V  to  1'8"  at  the  top.     This  change 
was  a  betterment  essential  to  the  safety  of  the  structure. 

8.  Power  House  Floor. — The  original  plans  provided  for  a  reinforced  con- 
crete floor  supported  on  I-beams.     The  floor  as  built  was   supported  partially 
on  earth  fill  and  partially  on  reinforced  concrete  beams.    Assuming  this  work 
was  properly  done,  this  change  was  an  improvement  on  the  plans. 

9.  Changes  in  Head  Gate  Racks. — The  racks  as  originally  designed  and  in- 
stalled permitted  drift  to  enter  the  penstocks,  which  caused  the  frequent  break- 
age of  the  turbine  gates.     The  change  in  form  of  rack  later  installed,  and  now 
in  place,  was  a  decided  betterment  which  accomplished  its  object,  although  it  in- 
terposed too  great  a  resistance  to  the  free  entrance  of  water. 

IMMATERIAL  CHANGES 

1.  Change  in  Width  of  Plans. — The  change  in  the  width  of  the  dam  from 
125'9"  to  93'  I  regard  as  immaterial.    If  the  dam  were  otherwise  safe,  either 
width  of  dam  would  be  safe  and  satisfactory.     The  narrower  design  is  more  eco- 
nomical and  therefore  an  improvement   from    an    engineering    standpoint,    but 
from  the  point  of  view  of  the  City,  the  change  is  immaterial. 

2.  Change  in  Bascule  Castings. — The  bascule  castings  for  the  gates  were 
changed  from  a  rack  type  to  a  plain  type.     Either  type  would  have  been  satis- 
factory if  sufficiently  strong  for  the  purpose,  and  if  the  gates  were  otherwise 
satisfactory. 

3.  Cutoff  Walls  below  Old  Dam. — A  cutoff  wall  was  planned  below  the  toe 
of  the  old  dam  but  was  omitted  in  construction.    If  this  wall  was  intended  to 
cut  off  flow  under  the  old  dam,  its  presence  would  have  been  a  detriment  rather 
than  a  benefit.     Seepage  should  be  stopped  at  the  heel  of  the  dam,  and  if  it 
reaches  the  toe  should  be  removed  instead  of  being  prevented,  in  order  to  reduce 
uplift  pressure  on  the  base  of  the  dam.     If  this  wall  had  been  installed,  weep 
holes  in  the  toe  would  have  become  essential.     The  omission  of  the  wall  at  the 
toe  is  regarded  as  immaterial. 

4.  Change  in  Concrete  Mixture. — A  change  was  made  in  the  mixture  of  the 
concrete  used  from  that  required  by  the  specifications  by  using  pit  run  sand  and 
gravel  instead  of  a  definite  mixture  of  cement,  sand  and  stone  or  screened  gravel 
in  the  ratio  of  1 :2  :4.     Mr.  Posey  states  (see  Appendix,  note  18,  page  75)  that  the 
pit  run  gravel  was  tested  frequently  for  voids,  and  the  voids  controlled  by  the 


20  Report  on  the  Dam  at  Austin,  Texas. 

addition  of  sand,  gravel  or  stone,  and  that  an  excess  of  cement  was  used.  The 
probabilities  are  that  the  concrete  produced  was  equal  to  that  which  would  have 
resulted  from  the  specified  mixture.  This  is  confirmed  by  the  appearance  of  the 
finished  work. 

DETBIMENTAL  CHANGES 

1.  Detrimental  Changes  in  the  Provisions  for  a  Safe  Foundation 

A.  Grouting. — The  specifications  for  grouting  were  very  indefinite.     Grout  com- 
posed of  cement  mixed  with  three  parts,  or  less,  of  sand  was  to  be  forced  into  two- 
inch  holes  of  unspecified  depth  which  were  to  be  spaced  not  more  than  30  feet  apart, 
or  any  other  method  could  be  used  to  render  the  substrata  impervious.     (See  Appen- 
dix, page  63.) 

Holes  were  bored  in  many  cases  very  close  together,  perhaps  in  cases  3  feet  or 
less  apart  but  near  the  line  of  the  cut-off  wall,  and  they  were  all  12  feet  or  less  in 
depth.  On  the  lines  of  the  cross  walls,  the  holes  in  general  were  bored  only  about  4 
or  5  feet  in  depth. 

The  general  purpose  of  this  specification  was  to  produce  an  impervious  bottom 
"to  prevent  waste"  but  the  safety  of  the  structure  was  more  particularly  involved. 
The  inadequacy  of  the  work  done  is  indicated  by  the  leaks  now  in  evidence  under  the 
reinforced  concrete  structure.  It  is  believed  that  the  grouting  behind  the  old  dam 
is  also  ineffective  in  preventing  seepage  and  uplift  pressure.  This  work,  which  was 
indefinitely  specified  except  as  to  its  object,  has  been  done  in  an  ineffective  and  in- 
complete manner,  and  the  conditions  resulting  threaten  the  safety  of  the  structure. 

B.  Cut-off  Wall  Above  West  Section  of  the  Old  Dam. — The  original  plans  pro- 
vide for  a  cut-off  wall  adjoining  the  heel  or  upstream  face  of  the  old  dam.    Appar- 
ently, from  the  scale  of  the  original  drawing  this  wall  was  to  be  about  22  feet  or  more 
in  depth.     A  shallow  cut-off  wall  was  built  as  part  of  the  so-called  "core  wall"  behind 
the  east  section  of  the  old  dam.     No  cut-off  wall  was  built  behind  the  west  section 
of  the  old  dam  but  inadequate  grouting  was  substituted  in  shallow  holes  of  a  maxi- 
mum depth  of  12  feet,  to  the  detriment  of  the  work. 

C.  Cut-off  Walls  on  Reinforced  Concrete  Dam. — These  walls  were  to  be  carried 
down  to  ' '  solid  impervious  rock  which  borings  indicated  to  be  at  least  six  feet  in 
thickness."    The  original  drawings  indicated  that  these  walls  were  to  be  carried  to 
a  depth  of  22  feet  or  more  below  the  rockbed  of  the  river.     Under  parts  of  the  dam 
it  is  probable  that  no  six-foot  strata  of  solid  rock  were  available,  and  the  specifica- 
tions were  perhaps  impossible  so  far  as  that  requirement  was  concerned.     These  con- 
ditions made  the  deep  cut-off  proposed  imperative  for  safety,  but  the  only  substitute 
furnished  was  to  carry  the  wall  approximately  two  feet  into  solid  rock,  and  to  at- 
tempt to  solidify  cracks  and  fissures  by  grouting.     In  places,  however,  according  to 
the  evidence  of  the  Inspecting  Engineer,  not  even  a  wall  two-feet  in  depth  was  con- 
structed. 


Changes  in  Plans.  21 

2.  Detrimental  Changes  in  the  Structure  of  the  Dam  and  Appurtenances 

A.  Core  Wall. — The  core  wall  as  shown  on  the  plans  and  as  described  in  the  spe- 
cifications is  somewhat  indefinite.     The  original  plans  submitted  with  the  contract 
show  the  bottom  of  the  east  end  of  the  core  wall  at  about  elevation  120.     The  revised 
detailed  plans  of  May,  1912,  show  the  end  of  this  wall  lowered  to  elevation  100. 
This  change  is  an  apparent  improvement.     The  original  plans  also  show  the  top  of 
the  core  wall  in  front  of  the  gate  masonry  to  be  at  about  elevation  172.     Evidently 
it  was  intended  to  face  the  head  gate  masonry  with  the  concrete  of  this  core  wall  in 
order  to  make  the  masonry  water  tight.     A  slight  modification  was  made  in  the  end 
of  the  core  wall  as  planned  when  it  was  constructed,  several  hundred  yards  of  con- 
crete being  omitted  by  the  consent  of  the  City's  Engineer  and  approved  by  the  City 
Council.     As  the  material  at  this  point  was  found  to  be  impervious,  this  change  is  ap- 
parently of  little  moment.     The  concrete  in  front  of  the  head  gate  masonry  was  om- 
itted, which  was  evidently  a  detriment  to  the  work  as  this  masonry  is  said  to  leak 
when  the  reservoir  is  full. 

B.  Pointing  the  Old  Dam. — While  the  old  masonry  has  been  pointed  in  part, 
this  work  has  not  been  done  in  a  thorough  and  workmanlike  manner. 

C.  Changes  in  Gates  and  Setting. — The  original  plans  for  the  gates  showed  a 
fairly  well  braced  gate,  but  when  the  gates  were  widened  and  redesigned  they  were 
built  in  two  sections  joined  only  by  thin  plates  which  were  to  be  supported  on  small 
bascule  piers.     While  neither  design  is  considered  adequate,  the  change  is  consid- 
ered detrimental.     The  introduction  of  small  center  bascule  piers  to  support  the  gates 
and  reduce  the  cost  of  their  construction  was  a  detriment  inasmuch  as  these  piers  ser- 
iously obstructed  the  flow. 

D.  Sluice  Gates  and  Sluice  Gate  Trash    Racks. — The    design    for    the    original 
sluice  gates  provided  for  the  sluice  gate  to  be  set  in  a  recess  in  the  dam,  built  in 
such  manner  that  the  hydraulic  cylinders  would  be  within  the  dam  and  accessible  at 
all  times  (see  A,  Fig.  7,  page  22).     This  plan  also  provided  for  T-rail  trash  racks  in 
front  of  the  gates  to  prevent  floating  matter  entering  the  gateways  and  interfering 
with  the  proper  operation  of  the  gates.     In  the  construction  of  the  plant  this  plan 
was  changed.     The  gates  together  with  the  hydraulic  cylinders  were  set  on  the  face 
of  the  dam  (see  B,  Fig.  7)  and  no  trash  racks  were  provided.     This  change  was   a 
decided  detriment. 

3.  Power  Plant  Accessories 

A.  The  Tail  Race. — Specifications  for  the  tail  race  evidently  anticipated  its  ex- 
cavation through  earth  and  the  construction  of  a  tunnel  or  channel  of  reinforced 
concrete  ample  for  the  use  of  the  three  turbines  installed  and  for  an  additional  tur- 
bine which  might  be  added  at  a  later  date.  It  was  found,  however,  that  the  surface 
of  the  rock  was  not  far  below  elevation  100  (low  water  level)  and  that  much  of  the 
excavation  would  have  to  be  made  in  rock ;  the  sum  of  about  $8,335  was  apparently 
expended  on  this  excavation.  The  presence  of  this  rock  rendered  concrete  unneces- 


22 


Report  on  the  Dam  at  Austin,  Texas. 


sary  except  that  a  wall  might  be  desirable  on  the  north  side  of  the  raceway  in  order 
to  keep  back  the  debris  from  the  large  mass  of  rock,  dirt,  etc.,  located  between  the 
tailrace  and  the  foot  of  the  dam.  (See  Figs.  8  and  9,  page  25.)  While  a  de- 
flecting wall  immediately  adjoining  the  power  house  and  north  of  this  raceway  is 
considered  advisable  in  order  to  protect  the  exposed  draft  tubes,  it  is  not  believed 


FIGURE   7 — Sections   of   Sluice   Gates   as   Originally   Designed   and 
as  Constructed. 

that  such  a  wall  extended  for  the  entire  length  of  the  raceway  in  the  main  channel 
would  be  either  effective  or  desirable.  To  be  effective  it  would  have  to  be  built  high 
and  strong  in  order  to  prevent  detritus  being  raised  over  it  in  times  of  extreme 
flood.  If  built  high  enough  for  this  purpose,  it  might  prove  objectionable  on  account 
of  creating  cross  currents  near  the  toe  of  the  dam  and  by  creating  a  comparatively 
quiet  pool  in  the  tailrace  which  would  cause  heavy  silt  deposits  therein.  The  re- 
quirements for  such  a  wall  can  best  be  obviated  by  the  entire  removal  of  this  pile  of 
debris.  While  the  failure  to  construct  a  concrete  channel  is  not  considered  detri- 
mental, the  failure  to  construct  a  proper  channel  which  would  not  be  filled  with  de- 
bris after  every  flood  is  considered  a  serious  detriment  to  the  work. 


Changes  in  Plans.  23 

B.  Penstocks. — The  penstocks,  or  intakes  as  they  are  termed  in  the  specifications, 
were  to  be  constructed  of  first  class  material  throughout  and  the  specifications  evi- 
dently did  not  anticipate  the  use  of  material  from  the  old  penstocks  installed  in  1893, 
and  which  had  remained  in  the  old  plant  until  the  removal  in  1911.     This  material 
was,  according  to  Mr.  S.  S.  Posey,  badly  corroded  but  was  used  for  all  of  the  pen- 
stock work  in  the  reconstructed  plant  except  for  the  elbows  which  were  of  new  ma- 
terial.    The  penstocks  outside  of  the  building  were  covered  with  reinforced  concrete ; 
inside  the  building  they  were  protected  on  the  inside  with  " smooth-on"  but  left  un- 
covered.    I  have  not  seen  these  penstocks  in  operation  and  cannot  speak  concerning 
their  tightness  and  effectiveness.     It  is  quite  possible  that  some  additional  protec- 
tion will  be  needed  inside  of  the  power  house.      While  these  penstocks  as  installed 
may  prove  fairly  satisfactory,  the  writer  considers  the  change  from  the  new  mater- 
ial to  the  old,  even  with  concrete  reinforcement,  as  detrimental  to  the  interests  of 
the  work. 

C.  Fourth  Penstock. — The   specifications  provide  for  four  penstocks  only  three 
of  which  will  be  used  in  the  present  plant,  the  fourth  being  reserved  for  an  additional 
unit  which  might  be  needed  later.     By  the  advice  of  the  City's  Engineer  and  with 
the  consent  of  the  City  Council  this  penstock  was  omitted  and  other  work  substi- 
tuted.    If  the  plant  is  to  be  utilized  finally  for  3300  average  continuous  horse  power, 
it  is  believed  that  the  omission  of  the  4th  penstock  was  evidently  a  mistake,  detri- 
mental to  the  installation.     While  I  am  not  fully  informed  as  to  the  load  factor  of 
the  Austin  electric  plant,  it  is  known  from  experience  that  the  load  factors  for  such 
plants  are  commonly  below  35  per  cent.,  and  that  it  is  hardly  probable  even  when 
Austin  is  able  to  utilize  the  full  3300  average  horse  power  that  this  load  factor  will 
increase  as  high  as  40  per  cent.     On  the  basis  of  35  per  cent,  load  factor,  the  maxi- 
mum peak  which  the  plant  must  carry  to  utilize  the  average  of  3300  HP  would  be 
almost  9500  HP,  and  if  the  load  factor  reaches  40  per  cent,  it  will  still  require  a  maxi- 
mum peak  of  about  8300  HP.     In  either  case  the  installation  of  an  additional  tur- 
bine, generator  and  penstock  will  finally  be  necessary  to  equip  the  plant  to  the  capa- 
city for  which  it  is  designed. 

D.  Draft  Tubes. — Both  the  original  plans  and  the  amended  plan  of  Jan.,  1912, 
showed  the  draft  tubes  within  the  power  house  and  discharging  through  the  founda- 
tion walls.     On  the  details  of  the  machinery  setting,    dated    November,    1912,    the 
draft  tubes  are  first  shown  projecting  in  the  exposed  position  in  which  they  were 
constructed.     This  change  is  detrimental  to  the  safety  and  continuous  operation  of 
the  plant. 

DEFECTS  IN  PRESENT  CONDITIONS  AND  STRUCTURES 

1.  Foundation  Conditions. — Having  pointed  out  the  various  changes  in  the  plans 
and  specifications  and  their  effect  on  the  installation,  it  is  necessary,  in  compliance 
with  instructions,  to  point  out  the  defects  in  the  present  installation,  only  part  of 


24  Report  on  the  Dam  at  Austin,  Texas. 

which  are  due  to  these  changes  the  remainder  being  due  to  their  inadequacy  and  in- 
completeness. 

The  serious  foundation  conditions  at  the  Austin  dam  have  been  discussed  at 
some  length  in  Appendices  1  and  4,  and  the  defects  in  the  present  structures  have 
been  described  in  considerable  detail  in  Appendix  5.  These  defects  may  be  de- 
scribed briefly  as  follows : 

A.  Foundation. — The  foundation  of  the  dam,  especially  of  the  new  part,  is  in 
very  bad  condition.    An  attempt  was  made  under  the  Johnson  contract  to  render 
this  bottom  impervious  by  grouting  which  however  was  inadequate  in  extent  and 
ineffective  in  results.     This  is  perhaps  the  most  serious  defect  in  the  work  done  and 
has  resulted  in  two  known  leaks,  and  unless   remedied  will  probably  result   in   the 
early  destruction  of  the  new  section  of  the  dam. 

B.  Riverbed  Below  the  Dam. — The  rock  below  the  toe  of  the  new  section  has  been 
deeply  eroded  and  is  in  general  considerably   below   the   foundations   of   the   cross 
walls  of  the  dam.     (See  Fig.   12,  page  28.)       The  irregular  foundations  of  these 
cross  walls  are  built  to  different  depths  and  founded  on  the  rough  and  irregular  sur- 
faces of  different  strata  of  rock,  which  will  prevent  the  slipping  of  the  dam  on  its 
foundations.     However,  there  is  a  danger  of  the  entire  structure  slipping  on  the  clay 
seams  which  are  known  to  underlie  at  least  a  part  of  the  structures.     A  dam  with  its 
foundation  above  the  bedrock  immediately  in  front  of  its  toe  cannot  be  regarded  as 
a  safe  structure,  and  the  present  condition  will  undoubtedly  be  made  worse  by  every 
high  flood. 

C.  Leakage. — The  large  leak  in  panel  No.  6  of  the  new  dam  was  discharging  ap- 
proximately 30  cubic  feet  per  second  during  the   writer's    examination    in   August, 
1917,  when  the  head  on  the  dam  was  only  15  feet.     This  leak  is  a  serious  menace  to 
the  structure.     The  leak  in  panel  No.  4,  while  apparently  small,  and  such  other  see- 
page as  may  occur  under  the  old  or  new  structure  may  increase  and  give  rise  ulti- 
mately to  dangerous  conditions. 

The  observations  of  the  U.  S.  Geological  Survey  (see  Appendix,  page  120)  show 
that  with  the  reservoir  full  to  elevation  151  there  is  leakage  into  the  strata  and 
around  the  dam  of  at  least  90  cubic  feet  per  second.  This  leakage  if  conserved  would 
under  a  sixty-foot  head  generate  about  600  continuous  horse  power,  and,  with  the 
power  utilized  to  even  half  of  the  rated  capacity  of  the  plant,  would  be  of  great  value 
during  low  water  seasons  or  for  about  55  per  cent,  of  the  time  (on  the  basis  of  the  flow 
for  the  last  20  years).  On  the  basis  of  $65  per  year  per  horse  power,  which  is  essen- 
tially equivalent  to  one  cent  per  kilowatt  hour,  the  annual  value  of  this  loss  by  leak- 
age would  be  about  $17,850,  which  amount  capitalized  at  ten  per  cent,  would  equal 
$178,500  which  is  an  approximate  measure  of  the  amount  which  may  ultimately  be 
expended  to  advantage  in  stopping  such  losses. 


Changes   in  Plans. 


25 


FIGUKE  8— Showing  Debris  North  of  the  Tailrace  and  the  Filling  of  the  Tailrace  by  the  Flood  of  Sep- 
tember,   1915,   also    Showing    the    Exposed  Position  of  the  Draft  Tubes. 


FIGURE  9 — Showing  Debris  North  of  the  Tailrace  and  the  Filling  of  the  Tailrace  by  the  Flood  of  Sep- 
tember,   1915,   also    Showing   the    Exposed   Position   of   the   Draft   Tubes. 


26  ;  Report  on  the  Darn  at  Austin,   Texas. 


FIGURE    10 — Showing    Drift    Accumulated    above  the  Dam  at  Austin  during  the  Flood  of 

September,   1915. 


FIGURK    11 — Showing    Drift    Accumulated    above  the  Dam  at  Austin  during  the  Flood  of 

September,   1915. 


Changes  in  Plans.  27 

2.  The  Structure  of  the  Dam 

A.  Old  Dam  Section. — The  specifications  provide  that: 

"portions  of  the  original  dam  as  constructed  in  1890-1893  will  be  retained  and 
used  as  portions  of  the  finished  structure.  *  *  The  contractor  assumes  the 
responsibility  for  the  perfect  stability  and  effectiveness  of  the  old  dam  as  part 
of  the  finished  structure." 

In  Appendix  5,  pages  124  to  129, 1  have  analyzed  the  section  of  the  old  dam  under 
the  various  conditions  of  its  past  and  proposed  use  and  have  found  that  it  cannot  be 
considered  as  safe  under  the  conditions  which  do  or  probably  will  obtain.  The  in- 
terior masonry  is  of  a  poor  quality  of  limestone  of  local  origin,  poorly  laid  in  cement 
mortar.  The  dam  is  faced  with  a  good  quality  of  granite  which  however  is  not  well 
bonded  into  the  interior  masonry.  Water  finds  ready  access  through  the  voids  to 
almost  every  part  of  the  structure.  The  facing  on  the  east  end  of  the  west  portion 
of  the  dam  is  apparently  loosened  from  the  underlying  masonry  and  shows  signs 
of  considerable  seepage  when  the  reservoir  reaches  elevation  151  or  higher. 

I  believe  there  is  a  real  danger  of  the  destruction  of  the  old  section  if  it  is  al- 
lowed to  remain  in  its  present  condition. 

B.  Crest  Gates. — The  gates  which  were  installed  on  the  reconstructed  dam  were 
about  18  feet  in  width,  placed  between  piers  two  feet  in  thickness  and  spaced  20  foot 
centers.     The  gates  were  entirely  inadequate  to  meet  the  contingencies  of  flood  flow 
and  the  piers  are  so  close  together  as  to  prevent  the  passage  of  the  large  masses  of 
drift  which  come  down  with  the  floods  of  the  Colorado.     (See  Figs.  10  and  11,  page 
26.) 

The  expense  involved  in  the  construction  of  the  gate  piers  and  gates  was  not 
large,  probably  amounting  to  about  $40,000,  and  would  have  been  warranted  if  the 
gates  could  have  been  cheaply  maintained  and  successfully  operated.  I  believe  how- 
ever that  practically  no  gates  which  can  be  installed  can  successfully  pass  the  heavy 
drift  of  the  Colorado  at  times  of  great  floods  without  great  difficulty  and  large  ex- 
pense. The  construction  of  any  gates  which  may  be  expected  to  take  care  of  these 
conditions  in  a  reasonably  economical  manner  will  cost  about  $363,000.  (See  Appen- 
dix 7,  page  173.)  An  analysis  of  the  comparative  power  which  would  be  available 
at  60  and  65  foot  heads  shows  that  the  extra  power  available  with  the  65-foot  head 
is  not  sufficient  to  pay  the  interest,  depreciation  and  maintenance  on  such  gates  and 
that  the  dam  can  be  more  economically  maintained  at  the  60-foot  head.  (See  Appen- 
dix 6,  pages  144  et  seq.) 

C.  Sluice  Gates. — The  sluice  gates  are  improperly  set  and  poorly  designed ;  two 
of  them  are  now  out  of  use.     The  sluiceways  were  partially  destroyed  on  account  of 
defective  design.     No  racks  were  provided  to  prevent  the  clogging  of  these  gates. 

D.  Passageway  in  the  Dam. — The  passageway  in  the  dam  is  provided  with  a 
wooden  walk  which  is  in  a  weakened  condition  from  decay  and  soon  will  be  unsafe. 
Its  railing  has  not  been  painted  and  is  badly  corroded. 


28 


Report  on  the  Dam    at  Austin,  Texas. 


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FIGURE  12  —  Sections  of  the  Austin  Dam  Showing  Erosion   below   the   Toe 
and  Depth  of  Erosion  below  Foundations  of  New  Dam. 

(Fractured  and  laminated  conditions  of  the  f  oxidation  rock  probably  exaggerated  to  illustrate  possible  danger  of  sliding.) 


Changes  in  Plans.  29 

3.  Plant  Accessories 

A.  Head  Gate  Masonry. — The  head  gate  masonry  is  said  to  leak  considerably 
when  the  reservoir  is  full. 

B.  Head  Gate  Trash  Racks. — The  head  gate  trash  racks  are  improperly  built  to 
admit  water  freely  to  the  penstock. 

C.  Head  Gate  Hoists. — The  head  gate  hoists  are  of  a  cheap  and  inadequate  de- 
sign, such  as  are  ordinarily  used  only  on  country  mill  dams. 

D.  Tail  Race. — The  tail  race  is  partially  filled  and  is  probably  of  insufficient 
depth.     With  the  great  pile  of  debris  between  it  and  the  dam  every  considerable 
flood  will  obstruct  the  raceway  by  washing  in  material  from  that  source. 

E.  Draft  Tubes. — The  draft  tubes  are  exposed  to  the  drift  which  accompanies 
every  flood.     The  north  one  has  already  been  injured  by  floating  drift.     They  have 
been  rendered  temporarily  tight  by  the  use  of  Portland  cement  mortar  but  are  ap- 
parently not  in  satisfactory  condition. 

F.  Pumps. — Of  the  three  pumps  of  four-million  gallons  capacity  each,  furnished 
in  lieu  of  two  pumps  of  6-million  gallons  capacity  each  in  accordance  with  the  con- 
tract, the  one  installed  at  the  north  station  has  been  broken  through  the  discharge 
nozzle  by  the  strain  set  up  on  account  of  the  imperfect  alignment  of  the  discharge 
piping.     Of  the  two  installed  in  the  main  pumping  station,  one  is  badly  worn  with 
sand  to  an  extent  which  must  make  its  operation  exceedingly  inefficient.     The  bear- 
ings on  all  of  these  pumps  are  said  to  heat  badly  during  operation. 

Gr.  Station  Equipment,  etc. — The  general  condition  of  the  penstocks,  station 
equipment,  and  many  other  details  cannot  be  well  ascertained  until  the  plant  is  put 
into  operation.  Undoubtedly  some  defects  may  be  expected  to  develop  in  addition 
to  those  enumerated  above. 

REMEDIES 

1.  Foundation  Conditions 

A.  Foundation  at  the  Heel  of  the  Dam. — The  foundation  rock  at  the  heel  of  the 
dam  should  be  rendered  practically  impervious  by  grouting  through  holes  spaced  not 
more  than  six  feet  apart,  and  in  two  rows  spaced  about  six-foot  centers,  the  holes  of 
one  row  alternating  with  those  of  the  second  row.     The  holes  should  be  at  least  50 
feet  in  depth  and  the  grout  should  be  of  slow   setting  Portland  cement  used  neat. 
The  work  must  be  done  with  every  care  and  precaution. 

A  cut-off  wall  should  be  constructed  above  the  heel  or  upstream  face  of  the  new 
section,  and  should  be  carried  from  15  to  30  feet  in  depth,  according  to  the  effective- 
ness of  the  grouting  work.  Unless  the  grouting  work  is  found  thoroughly  effective, 
a  cut-off  wall  of  at  least  10  feet  in  depth  should  be  constructed  along  the  heel  of  the 
old  section. 

B.  Leaks  Under  the  New  Section. — These  leaks  may  be  stopped  by  the  work 
above  outlined  on  the  dam  foundation.    If  not  they  must  be  shut  off  by  still  deeper 


30  Report  on  the  Dam  at  Austin,  Texas. 

and  more  thorough  grouting  at  and  immediately  adjoining  the  fissures  where  the 
leaks  now  appear.  In  any  event,  the  fissures  should  be  well  filled  with  grout,  mor- 
tar or  concrete. 

C.  Improvements  Below  Toe  of  Dam. — The  depression  below  the  toe  of  the  new 
section  must  be  filled  with  concrete  which  must  be  brought  to  an  elevation  above 
the  footing  of  the  cross  walls  of  the  dam  in  such  manner  as  to  give  them  a  substan- 
tial bearing  and  resistance  against  sliding.  This  apron  should  be  sufficiently  heavy 
to  prevent  further  scouring  by  flood  waters  and  should  extend  downstream  to  the 
rock  ledge  on  which  the  mass  of  debris  now  lies. 

A  fifty-foot  apron  in  front  of  the  old  section  is  considered  desirable,  but  possibly 
not  essential  at  the  present  time  if  the  bottom  is  watched  and  repaired  whenever  in- 
dications of  any  erosion  by  the  flood  waters  appear.  Weep  holes  should  be  pro- 
vided through  all  aprons  to  prevent  uplift  pressure  from  springs  or  seepage  waters. 
2.  Dam  Structure 

A.  Crest  of  Dam. — The  crest  piers  and  gates  on  the  dam  should  be  removed  and 
the  crest  of  the  reinforced  concrete  structure  brought  to  the  same  elevation  as  the 
crest  of  the  old  structure. 

B.  Old  Dam  Section. — The  foundation  and  structure  of  the  old  dam  should  be 
filled  with  cement  grout  and  the  section  should  be  reinforced  with  concrete,   essen- 
tially as  shown  in  Appendix  8,  page  183. 

C.  Reduction  in  Seepage  Around  Dam. — The  rock  bluff  west  of  the  dam  should 
be  grouted  to  reduce  or  prevent  seepage.     Excavations  should  be  made  along  the 
east  bluff  where  leakage  is  known  to  occur,  and  all  the  cavities  should  be  properly 
filled  and  sealed.     A  careful  examination  should  be  made  of  the  pervious  strata  in 
which  these  leaks  occur,  and  if  further  work  in  reducing  the  leakage  seems  feasible 
it  should  be  undertaken. 

D.  Walk  in  Dam. — A  reinforced  concrete  walk  should  be  constructed  to  replace 
the  wooden  walk  in  the  old  dam  and  the  railing    should   be   cleaned   from    rust   and 
thoroughly  painted. 

E.  Sluice  Gates  and  Sluiceways. — The  sluice  gates  should  be  rebuilt  or  repaired 
in  a  substantial  and  permanent  manner.      The    sluiceway    should    be    strengthened 
where  necessary  and  the  one  which  has  not  been  repaired  should  be  repaired  in  a 
substantial  manner. 

F.  Inspection  of  Foundation  Under  Dam. — During  the  construction  of  the  apron, 
the  inside  of  the  hollow  dam  should  be  cleaned  out  and  the  bottom  carefully  exam- 
ined for  signs  of  additional  leaks. 

3.  Plant  Accessories 

A.  Head  Gate  Masonry. — The  head  gate  masonry  should  be  grouted,  pointed 
and  rendered  essentially  water  tight. 

B.  Head  Gate  Trash  Racks. — The  head  gate  trash  racks  should  be  rebuilt  so  that 
the  openings  shall  be  from  iy2  to  1%  inches  in  width,  and  the  rack  supports  should 
be  strengthened  if  found  necessary. 


Estimated  Cost  of  Improvements.  31 

C.  Tailrace. — The  pile  of  debris  between  the  tailrace  and  the  old  dam  should  be 
removed,  the  tail  race  cleaned,  and  sufficient  rock  excavated  to  give    the    waters 
from  the  draft  tubes  a  free  discharge  and  a  maximum  velocity   of  not   more   than 
three  feet  per  second. 

D.  Defecting  Wall. — A  deflecting  wall  should  be  built  to  protect  the  draft  tubes 
from  floating  drift. 

E.  Railing. — A  railing  should  be  constructed  from  the  face  of  the  old  dam  down 
the  abutment  and  along  the  retaining  wall  to  the  station  building  to  protect  the  pub- 
lie. 

ESTIMATED  COST  OF  BETTERMENTS,  CHANGES  AND  IMPROVEMENTS 

The  following  is  a  summary  of  the  writer's  estimate  of  the  cost  of  the  better- 
ments previously  recommended: 

Foundation  Grouting  and  Cut-off  Wall: 

Grouting,  25,000  ft.  of  drilling  holes  at  $3  per  ft $75,000 

Cut-Off  Wall  New  Dam,  5  ft.  wide  30  ft.  deep 

Excavation  3500  cu.  yds.  at  $3 $10,500 

Concrete  3500  cu.  yds.  at  $7  24,500 

35.000 

Old  Dam,  3  ft.  wide  10  ft.  deep 10,000 

Apron  for  Dam,  12,000  cu.  yds.  at  $7  84,000 

Cofferdam    50,000 

Crest  of  Dam,  Removing  Crest  Pier $10,000 

1,650  cu.  yds.  Concrete  at  $20 33,000 

140,000  Ibs.  Steel  at  7c 10,000 

—  53,000 

Reduction  of  Seepage  around  Dam 25,000 

Improving  Old  Dam  Section  550  ft.  at  $210  per  ft 115,500 

Tailrace,  Removal  of  Debris  and  Deepening  Raceway    15,000 

Deflecting  Wall,  180  yds.  at  $12 2,200 

Head  Gate  Racks,  Reconstruction   300 

Concrete  Walk  in  Old  Dam  2,000 

Repairs  to  Sluice  Gates  and  Sluiceways 10,000 

Railing  along  Retaining  Wall 100 

Cleaning  and  Inspecting  Rock  Floor  of  New  Dam    400 


$477,500 
Engineering  and  Contingencies  and  Misc.  Expense  20  per  cent 95,500 


Total   $573,000 


32  Report  on  the  Dam  at  Austin,  Texas. 

CHARACTER  OF  THE  ESTIMATE 

In  considering  the  above  estimate  it  is  obvious  that  there  are  many  uncertainties 
concerning  the  costs  of  some  of  these  items.  The  structures  are  built  and  parts  of 
them  are  inaccessible ;  their  conditions  have  been  judged  from  the  descriptions  of 
others  and  from  soundings  of  the  rock  bottom  now  concealed  by  water  and  debris. 
The  pervious  rock  strata  along  the  east  bluff  are  also  largely  concealed  by  earth. 
The  expense  which  will  be  involved  where  such  contingencies  exist  has  been  cov- 
ered by  liberal  estimates.  A  contingent  item  has  been  added  to  care  for  extraordi- 
nary conditions  of  strata,  floods,  etc.,  and  for  other  betterments  which  may  be  found 
necessary  when  an  attempt  is  made  to  put  the  plant  into  operation.  I  believe  that 
the  estimates  will  cover  the  necessary  expense  involved  in  the  construction  of  these 
betterments,  and  it  is  quite  possible  that  a  substantial  saving  may  be  effected  if  con- 
ditions are  favorable.  I  do  not  believe,  however,  that  it  is  safe  to  estimate  the  work 
on  any  lower  basis. 

PERMANENCY  OF  THE  STRUCTURES 

I  have  been  instructed  to  report  on  the  "  permanency  of  the  structures  for  all 
probable  time  and  suggest  such  additional  things,  if  any,  proper  to  be  done  to  make 
such  structures  permanent,  stable  and  efficient." 

I  have  previously  outlined  various  improvements  and  betterments  which  I  be- 
lieve will  render  the  work  permanent,  safe,  substantial  and  fit  for  the  service  of  the 
City,  provided  the  execution  of  the  work  is  thoroughly  and  conscientiously  done. 

A  detailed  analysis  of  the  stresses  in  the  reinforced  concrete  dam  shows  that  the 
structure  is  safe.  The  maximum  stresses  in  the  steel  reinforcement  are  somewhat 
greater  than  good  practice  would  warrant,  reaching  as  high  as  23,000  pounds  per 
square  inch  instead  of  16,500  pounds  which  was  said  (see  page  134)  to  have  been  the 
basis  of  design.  Considering  the  character  of  reinforcing  steel,  this  stress  is  not  so 
great  as  to  lead  to  any  fear  of  rupture.  I  believe,  however,  that  a  solid  dam  would 
have  been  a  safer  though  probably  a  more  expensive  structure.  Many  high  reinforced 
concrete  dams  are  in  use  at  the  present  day,  though  it  still  remains  to  be  seen  how 
permanent  they  will  be  after  long  years  of  service.  The  dam  will,  in  my  opinion, 
fulfill  its  functions  for  more  than  25  years  and  may  ultimately  show  that  the  econo- 
mies resulting  from  such  a  type  of  design  are  warranted. 

There  are  two  risks  involved  in  this  project  on  which  I  am  unable  to  give  full 
assurance : 

1st.  Will  the  leakage  around  and  under  the  dam  greatly  exceed  the  esti- 
mate of  this  report? 

If  the  estimated  leakage  is  exceeded,  the  power  estimate  will  be  too  high,  and 
this  value  of  the  power  which  can  be  generated  will  be  reduced  unless  the  leakage 
can  be  partially  or  wholly  eliminated. 


Permanency  of  the  Structures.  33 

2d.  Will  deep  leakage  under  the  dam  endanger  that  structure? 
The  fact  that  the  old  dam  stood  from  1893  to  1900  without  developing  serious 
deep  leakage  and  finally  went  out  from  entirely  different  reasons,  is  a  fair  measure 
of  safety,  and  I  am  of  the  opinion  that  with  the  precautions  suggested  the  dam  will 
remain  a  safe  and  substantial  structure. 

I  believe  if  the  betterments  outlined  are  carried  out  with  proper  care,  the  risk 
involved  in  the  permanency  of  the  structure  will  be  small.  I  would  advise,  how- 
ever, that  after  these  betterments  are  completed  and  the  plant  is  placed  in  opera- 
tion, the  City  have  an  examination  of  this  structure  made  annually  by  an  engineer 
experienced  in  the  construction  of  dams,  in  order  to  detect  and  remedy  any  defects 
which  may  possibly  develop. 

Value  of  Material  and  Labor  in  Place. — The  material  and  labor  in  place  have 
been  estimated  on  the  basis  of  prices  prevailing  at  the  time  the  structures  were  under 
construction.  These  estimates  are  discussed  and  shown  in  detail  in  Appendix  9. 
They  are  here  summarized  as  follows: 

Reservoir   $43,650 

Power  House,  Penstocks,  Pole  Lines,  etc 37,773 

Machinery  and  Equipment 99,624 

Dam 491,660 

Extras 13,792 


Total    $686,499 


In  accordance  with  instructions  contained  in  a  letter  from  Mayor  Wooldridge 
dated  September  14,  1917  (see  page  4).  I  have  given  thoughtful  consideration 
to  the  matter  of  responsibility  for  the  cost  of  the  betterments  necessary  to  make  this 
dam  a  safe,  stable  and  useful  structure. 

Such  a  division  of  responsibility  is  desirable  if  possible  but  such  limits  are  diffi- 
cult to  fix.  The  exact  line  between  safety  and  danger  is  indefinite.  No  one  can  say 
that  if  a  certain  definite  number  of  dollars  are  spent  on  these  betterments  safety  will 
be  assured,  that  if  a  few  dollars  less  are  spent  the  dam  will  be  in  danger,  and  that  if 
a  few  dollars  additional  are  expended  the  money  will  be  wasted.  In  the  construc- 
tion of  a  dam,  in  order  to  be  safe  the  design  must  carry  the  structure  well  beyond 
the  lines  of  danger  and  well  within  the  zone  of  safety  in  order  to  provide  for  those 
unknown  factors  which  must  always  be  anticipated  in  engineering  works.  It  is 
therefore  somewhat  difficult  to  separate  the  responsibility  for  additional  work  called 
for  or  fairly  implied  by  the  terms  of  this  contract  from  these  things  which  must  be 
done  yet  are  not  specified  in  the  contract  which  contains  a  specific  guarantee  for  25 
years  maintenance.  In  such  analysis  the  meaning  and  intent  of  the  contract  are 
fully  as  important  as  the  written  word. 


34  Report  on  the  Dam  at  Austin,  Texas. 

The  City  of  Austin  elected  to  pay  a  second  party  a  fixed  sum  plus  an  annual 
rental,  to  do  the  work  and  to  assume  the  responsibility  of  both  constructing  and 
maintaining  this  dam  for  a  period  of  25  years.  This  plan  seemed  plausible  and 
proper  guarantees  seemed  feasible,  and  the  plan  was  legalized  by  an  act  of  the  Leg- 
islature specifically  authorizing  this  form  of  contract. 

The  City  failed  to  see  that  the  responsibility  of  the  promoter  was  the  only  ele- 
ment that  gave  the  guarantees  value,  and  that  the  only  factors  which  would  render 
the  guarantees  of  the  promoting  company  of  real  worth  were: 

1st.  The  money  which  the  City  itself  must  pay  to  this  Company. 
2d.  The  success  of  the  plans  which  the  promoters  might  elect  to  carry  out. 
3d.  The  money  which  the  promoters  might  borrow  through  the  faith  of  in- 
nocent parties  in  the  validity  of  the  contract  and  on  the  standing  of  the  City  of 
Austin. 

As  a  matter  of  fact,  if  the  promoters  failed  to  complete  the  work  the  City  was  out 
nothing,  but  the  burden  was  shifted  not  to  the  shoulders  of  the  promoters  but  to  the 
shoulders  of  their  creditors.  The  promoters  on  their  part  had  nothing  to  lose  and 
everything  to  gain.  They  did  not  propose  to  put  their  own  money  into  the  venture 
but  to  carry  their  endeavor  on  borrowed  capital,  and  to  shift  the  risk  which  they  ap- 
parently assumed,  on  innocent  parties  who  had  no  means  of  knowing  or  appreciating 
the  risks  involved. 

These  promoters  proposed  to  the  City  of  Austin  to  construct  certain  works  for 
payments  having  an  aggregate  present  value  of  a  million  dollars,  and  they  hoped  to 
secure  a  return  of  one-half  this  amount  for  promoting  and  financing  the  scheme. 
They  attempted  to  build  for  less  than  $500,000  structures  which  could  not  be  built 
properly  and  safely  under  the  conditions  which  obtained  during  the  period  of  con- 
struction, for  less  than  the  entire  million  dollars  involved  in  their  contract. 

The  City  fixed  its  faith  on  guarantees  which  were  elaborately  described  in  the 
franchise  ordinance  but  were,  under  the  circumstances  and  for  the  purpose  of  se- 
curing satisfactory  construction,  the  least  essential  feature  of  a  contract.  The  pro- 
moters furnished  incomplete  plans  and  indefinite  specifications,  and  rendered  them 
both  even  more  uncertain  by  the  provision  that  their  Engineer  could  modify  them 
at  his  will  provided  that  he  did  not  l '  decrease  the  amount  of  equipment  in  the  power 
house,  the  height  or  stability  of  the  dam,  the  size  of  the  reservoir,  or  in  any  wav 
diminish  the  capacity  or  completeness  of  the  installation  or  in  any  way  lower  the 
standard  or  grade  of  construction." 

Having  secured  the  contract,  the  promoters  immediately  began  work  in  order  to 
fulfill  the  required  terms  of  progress.  A  stock  company  was  organized  for  financ- 
ing the  proposition,  to  which  the  franchise  was  assigned  and  by  which  means  all 
individual  responsibility  was  avoided.  A  contractor  was  induced  to  undertake  the 
work  for  a  fixed  sum,  with  a  provision  that  if  any  reduction  in  the  cost  of  the  work 
was  possible,  two-thirds  of  the  saving  would  be  credited  to  the  promoting  company. 


Responsibility  for  Cost  of  Improvements.  35 

Every  effort  seems  to  have  been  made  to  reduce  the  cost  of  every  feature  of  the  work 
to  the  utmost. 

The  City  apparently  approved  these  vague  and  imperfect  plans  and  specifica- 
tions solely  on  the  basis  of  valueless  guarantees,  and  appointed  an  Engineer  who 
apparently  approved  the  construction  on  the  same  basis.  The  City  naturally  has  re- 
fused the  acceptance  of  the  work  because  these  guarantees  have  not  been  fulfilled. 

There  has  been  expended  on  this  work  about  $750,000,  or  more  than  50  per  cent, 
in  excess  of  the  cost  for  which  the  promoters  expected  to  construct  it.  To  put  the 
work  into  safe  condition  so  that  it  will  successfully  perform  the  functions  for  which 
it  is  intended  will  cost  still  more  than  the  promoters '  original  estimate  for  the  cost 
of  the  entire  work. 

Grouting  and  cut-off  walls  were  required  by  the  contract.  The  cut-off  walls 
were  eliminated  and  the  grouting  might  almost  as  well  have  been  omitted  so  far  as 
results  are  concerned,  for  the  work  done  was  entirely  insignificant  in  view  of  the 
amount  of  such  work  required  for  safety. 

The  promoters  assumed  responsibility  for  those  portions  of  the  old  dam  which 
they  proposed  to  utilize,  although  they  knew  that  conditions  might  arise  under  which 
it  would  be  unstable.  In  the  original  report  of  their  Engineer  the  statement  was 
made  that: 

"The  dam  therefore  will  require  some  additional  masonry.  This  is  simply 
to  assure  beyond  any  possible  doubt  stability  under  any  flood  that  may  ever 
come  down  the  river.  The  dam  may  be  looked  on  as  reasonably  safe  as  it  now 
stands. ' ' 

Their  Engineer  advised  that: 

' ;  The  section  of  the  old  dam  should  be  strengthened  by  the  addition  of  a 
mass  of  concrete  well  bonded  in  the  granite  of  the  structure. ' ' 

No  such  improvement  was  provided  in  the  plans  submitted  to  the  City  of  Aus- 
tin, and  even  the  cut-off  wall  planned  at  the  heel  was  omitted.  It  is  my  opinion  that 
the  old  structure  is  unsafe  as  it  now  stands  and  that  unless  radical  changes  are 
made  it  will  be  destroyed  in  less  than  25  years  unless  it  is  again  relieved  from  danger 
by  the  destruction  of  the  new  section  which  is  liable  to  early  failure  unless  its  foun- 
dation is  rendered  stable  and  impervious. 

No  provision  was  made  in  the  specifications  for  an  apron  below  the  toe  of  the 
dam.  It  was  known  that  a  deep  trench  had  been  formed  along  this  toe  by  flood  waters 
and  that  the  trench  was  largely  responsible  for  the  destruction  of  the  dam  in  1900. 
The  cross  walls  of  the  new  structure  were  apparently  carried  into  fairly  substan- 
tial material  yet  the  average  depth  of  these  foundations  was  left  considerably  above 
the  old  trench  which  lies  immediately  below  them.  The  condition  creates  a  real 
danger  of  the  new  structure  sliding  on  the  underlying  strata;  and  even  if  it  be  found 
by  experience  that  the  conditions  have  a  slight  balance  of  safety,  the  frequently  re- 


36  Report  on  the  Dam   at  Austin,  Texas. 

curring  floods  will  deepen  this  channel,  undermine  the  structure,  and  ultimately  de- 
stroy it.  This  condition  needs  an  immediate  remedy,  and  no  engineer  of  experience 
would  consider  the  structure  safe  at  the  present  time  ivith  the  conditions  as  they  now 
exist. 

The  expense  of  such  betterments  as  described  above  is  essential  for  the  safety  of 
the  structure.  In  view  of  the  guarantees  they  cannot  be  avoided  on  the  grounds  that 
they  were  not  specified. 

For  an  apron  below  the  old  structure,  the  necessity  is  not  so  imperative.  An 
apron  for  this  portion  of  the  work,  if  the  dam  is  otherwise  properly  strengthened,  is 
a  matter  of  extra  precaution  and  is  not  immediately  needed  for  safety  provided  the 
toe  is  carefully  watched  and  repairs  are  made  as  soon  as  their  necessity  is  indicated. 
Under  the  contract  the  responsibility  for  this  betterment  may  fairly  be  said  to  be 
with  the  City. 

I  believe  that  the  large  expense  involved  in  the  construction  and  maintenance 
of  proper  gates  is  unnecessary  and  undesirable.  This  expense  is  unwarranted  by 
the  additional  power  which  would  theoretically  be  developed ;  and  the  increased  leak- 
age, the  additional  evaporation  and  the  extra  stress  in  the  structure  which  would  be 
caused  by  the  additional  head,  still  further  reduce  the  desirability  of  gates.  The 
loss  due  to  their  elimination  can  be  at  least  partially  regained  by  a  reduction  in  leak- 
age through  the  pervious  strata  above  the  dam ;  and  while  the  cost  of  reducing  leak- 
age except  that  "immediately"  around  the  old  dam  is  eliminated  by  the  specifica- 
tion, the  cost  of  this  work  and  the  expense  of  raising  the  crest  of  the  new  section  to 
that  of  the  old  dam  is  an  inconsiderable  substitute  for  the  cost  of  the  installation  of 
proper  gates  and  their  expensive  maintenance. 

The  work  on  the  tail  race  has  not  been  properly  performed  and  the  expense  in- 
volved in  this  work  is  obviously  required  by  the  contract. 

The  draft  tubes  should  not  have  been  constructed  in  their  exposed  position. 
The  deflecting  wall  to  protect  these  draft  tubes  is  therefore  fairly  chargeable  under 
the  contract. 

The  head  gate  trash  racks  were  rebuilt,  I  understand,  on  the  design  of  the  City 's 
Engineer  and  according  to  his  instructions,  and  the  reconstruction  is  justly  charge- 
able to  the  City. 

The  timber  walkway  inside  of  the  old  dam  would  have  to  be  maintained  for  25 
years,  and  its  reconstruction  in  permanent  concrete  is  an  economy  fairly  chargeable 
to  the  promoters. 

The  repairs  to  the  sluice  gates  and  sluiceways  and  the  construction  of  sluice  gate 
trash  racks  are  made  necessary  by  faulty  design  and  neglect,  and  these  appurten- 
ances even  when  repaired  will  not  be  in  a  satisfactory  condition.  The  expense  of 
placing  them  in  a  condition  in  which  they  should  originally  have  been  constructed  is 
prohibitive  and  is  not  advised. 


Responsibility  for  Cost  of  Improvements.  37 

The  railing  along  the  retaining  wall  is  not  required  for  the  safety  of  the  struc- 
ture and  should  be  built  by  the  City  for  the  safety  of  the  citizens. 

It  is  my  opinion  that  with  the  exception  of  the  few  minor  items  specifically  men- 
tioned, the  cost  of  the  betterments  recommended  should  fairly  be  paid  by  the  pro- 
moting company  under  its  guarantee  to  build  this  dam  and  maintain  it  for  25  years. 

Such  a  finding,  however,  seems  absurd  where  the  facts  are  recognized  that  the 
officials  of  the  promoting  company  have  realized  their  failure  and  have  abandoned 
the  work  which  is  now  in  the  hands  of  a  receiver. 

Under  the  conditions  that  now  obtain  these  promoters  have  apparently  no  legal 
responsibility  and  they  certainly  have  few  rights  in  equity  which  the  City  is  bound  to 
respect.  The  promoters,  however,  transferred  their  financial  responsibility  to  the 
shoulders  of  their  creditors.  The  creditors  consist  of  the  assignee  of  the  Contractor 
who  performed  the  work  for  the  Promoters,  of  the  holders  of  the  bonds  issued  by  the 
Promoting  Company,  and  possibly  of  some  other  legitimate  claimants. 

On  the  basis  of  a  moderate  prospective  profit,  the  Contracting  Company  took  a 
contract  for  the  performance  of  certain  specific  things  which  the  City  had  approved 
as  sufficient  for  the  purpose,  and  in  their  contract  specifically  disclaimed  any  respon- 
sibility for  the  plans  involved.  The  work  done  is  apparently  first  class  in  every 
particular,  so  far  as  the  limits  of  the  defective  plans  and  specifications  provide.  The 
difficulties  that  have  arisen  and  the  defects  that  have  developed  are  not  those  caused 
by  defective  work  but  were  caused  by  defective  or  deficient  design,  for  which  the  Con- 
tractor is  in  no  way  responsible  in  equity  although  it  may  be  in  law. 

The  bond  holders  who  purchased  the  bonds  issued  by  the  Promoting  Company  are 
in  equity  even  less  responsible.  They  purchased  bonds  on  their  faith  in  the  City  of 
Austin  and  on  the  franchise,  specifications  and  plans  which  the  City  of  Austin  had 
approved  and  accepted. 

These  innocent  parties,  drawn  into  unfortunate  legal  complications  through  the 
efforts  of  promoters  to  secure  undue  profits,  are  worthy  of  the  fairest  consideration. 

As  the  enterprise  now  stands,  the  interests  involved  are  as  follows: 

1st.  The  City  Water  Power  Company,  bankrupt  with  apparently  no  assets 
except  a  franchise,  is  in  the  hands  of  a  receiver. 

2d.  The  Wm.  P.  Carmichael  Company  with  about  $500,000  invested,  has 
apparently  already  expended  $250,000  in  excess  of  its  claim  and  is  in  the  hands 
of  its  creditors. 

3d.  The  creditors  of  the  Wm.  P.  Carmichael  Company. 

4th.  The  purchasers  of  the  bonds  of  the  City  Water  Power  Company. 

5th.  Certain  creditors  who  hold  claims  directly  against  the  City  Water 
Power  Company. 

6th.  The  City  of  Austin  which  for  almost  thirty  years  had  endeavored  to  con- 
summate this  project. 


38  Report  on  the  Dam  at  Austin,  Texas. 

Only  the  abandoned  site  and  station  of  the  City  of  Austin  are  invested  in  this  en- 
terprise, with  the  exception  of  the  $21,000  advanced  the  Contractor,  which  is  less 
than  half  the  value  of  the  water  works  reservoir,  completed  in  1912,  and  used  by  the 
City  for  the  last  five  years. 

The  City,  however,  holds  the  key  to  the  situation  and  has  a  moral  if  not  a  legal 
obligation  to  effect  some  arrangement  whereby  the  situation  can  be  cleared  up  and 
the  endeavor  carried  to  a  successful  consummation  with  the  least  possible  injury  to 
all  concerned. 

From  my  study  of  this  unfortunate  situation  I  believe  the  only  practicable,  legal 
and  equitable  way  for  a  fair  adjustment  of  the  cost  of  the  necessary  betterments  for 
this  work  and  of  the  interests  involved  in  this  property  is  for  the  City  to  take  over 
the  property  on  some  fair  and  equitable  basis  and : 

1.  Either  make  a  new  contract  with  the   creditors   who   have   valid   claims 
against  the  work,  on  a  basis  which  will  enable  them  to  finance  the  cost  of  better- 
ments and  ultimately  recover  their  present  and  additional  investment; 

2.  Or  for  the  City  to  undertake  these  betterments  at  its  own  expense,  pay- 
ing to  the  legitimate  creditors  possibly  in  annual  installments,  a  fair  valuation 
for  the  work  already  done. 

The  water  power  property  as  it  stood  without  reconstruction  was  valueless. 
While  the  cost  of  the  necessary  betterments  is  large,  it  is  not  more  than  half  the  legi- 
timate cost  of  a  proper  reconstruction  of  the  property  as  it  stood  in  1910 ;  and  the 
cost  of  these  betterments  if  added  to  the  legitimate  outlays  that  have  been  made 
under  the  Johnson  contract,  will  be  more  than  warranted  by  the  value  of  the  prop- 
erty to  the  City. 

ULTIMATE  VALUE  OF  THE  PLANT 

As  a  basis  for  the  annual  payments  on  the  Johnson  contract,  the  value  of  the 
hydraulic  power  to  be  delivered  from  the  reconstructed  plant  was  evidently  esti- 
mated at  0.9c  per  horse  power  hour,  as  the  amount  of  the  minimum  power  (600,000 
HPH  per  month)  would  on  that  basis  equal  the  amount  of  the  annual  payments  of 
$64,800  per  year.  It  is  not  probable  that  the  saving  effected  by  the  annual  amount 
of  power  used  will  equal  this  amount  at  the  present  time,  as  the  cost  of  operation  and 
maintenance  of  the  hydraulic  plant  must  be  paid  by  the  City  and  the  saving  at  the 
steam  plant  will  include  only  the  cost  of  fuel,  certain  labor  and  certain  incidental  ex- 
penses. However,  taking  into  consideration  the  fact  that  there  would  be  additional 
power  besides  the  minimum,  which  could  promptly  be  utilized  to  secure  additional  in- 
come, and  that  the  payment  made  will  ultimately  result  in  the  acquisition  of  the 
plant  by  the  City,  this  annual  payment  would  be  entirely  warranted.  Furthermore, 
as  the  amount  of  the  power  demand  increases,  the  cost  per  unit  output  will  decrease, 
and  with  the  rise  in  the  cost  of  fuel  the  ultimate  value  of  the  horse  power  hour  of 


Responsibility  for  Cost  of  Improvements.  39 

hydraulic  power  compared  with  the  cost  of  generating  power  by  steam,  may  very 
properly  be  estimated  at  .9c  per  horse  power  hour. 

On  this  basis  the  average  annual  value  of  the  power  available  when  the  plant  is 
fully  utilized  is,  on  the  basis  of  a  60-foot  head,  equal  to  approximately  $190,000.  This 
capitalized  on  a  10  per  cent,  basis,  to  cover  interest  and  depreciation,  will  give  an 
ultimate  value  to  the  installation  of  approximately  $1,900,000,  which  is  a  fair  measure 
of  the  maximum  amount  which  ultimately  could  reasonably  be  expended  in  the  con- 
struction of  this  plant. 

t 

SUPERVISION  OF  THE  CONSTRUCTION  OF  BETTERMENTS 

The  proper  construction  of  the  betterments  recommended  in  this  report  is  just 
as  essential  as  the  betterments  themselves,  and  without  proper  workmanship  the  en- 
tire amounts  estimated  may  be  expended  and  the  dam  remain  unsafe.  No  ambition 
for  authority,  no  political  interference,  no  desire  for  profit  must  be  allowed  to  in- 
terfere with  thorough,  first  class  work.  The  work  should  be  intrusted  to  some  one 
who  has  had  extended  practical  experience  along  such  lines  of  work,  and  he  should 
be  given  such  authority  as  will  enable  him  to  complete  the  work  in  a  thorough  and 
workmanlike  manner.  If  uncertainties  arise  in  regard  to  any  matter  or  thing  con- 
nected with  the  work,  engineers  having  special  experience  should  be  consulted,  for 
the  saving  thus  affected  and  the  security  thus  gained  will  be  large.  The  City  ought 
not  to  run  further  risks  in  the  matter  of  safety  or  permanency  for  lack  of  sound  pro- 
fessional advice. 


APPENDIX   1 

HISTORY  OP  THE  AUSTIN,  TEXAS,  DAM 

For  a  full  understanding  of  the  present  (1917)  problem  of  the  Austin  dam,  and 
in  order  to  emphasize  certain  important  conditions  in  relation  thereto,  it  seems  es- 
sential to  review  briefly  the  history  of  the  endeavor  to  develop  power  by  the  construc- 
tion of  a  dam  across  the  Colorado  River  at  Austin,  Texas. 

As  early  as  January  4,  1839,  the  water  power  possibilities  of  the  Colorado  River 
at  Austin  were  pointed  out  by  the  Commissioners  for  the  location  of  a  permanent  site 
for  the  Capital  of  the  Republic  of  Texas. 

In  1871,  Mayor  John  W.  Glenn  had  surveys  made  above  and  below  Mt.  Bonnell 
to  determine  the  possibilities  of  developingwater  power. 

In  1873,  a  charter  was  granted  to  Judge  John  Hancock  and  others  authorizing 
the  erection  of  a  dam  across  the  Colorado  River  at  Austin,  which  was,  however,  al- 
lowed to  lapse. 

In  1876,  an  offer  from  an  Eastern  capitalist  to  build  a  dam  just  below  Mt.  Bon- 
nell was  refused  by  Mr.  P.  C.  Taylor,  owner  of  the  property. 

In  1887,  Captain  W.  C.  Walsh  called  attention,  in  a  letter  to  the  "Statesman" 
of  the  possibilities  of  irrigation  from  the  Colorado  River  by  the  construction  of  a 
dam. 

On  January  1, 1888,  Mr.  A.  P.  Wooldridge  (now  mayor)  advocated  the  construc- 
tion of  a  dam  in  a  communication  to  the  Board  of  Trade  of  Austin.  The  Board  of 
Trade,  after  due  consideration,  engaged  Mr.  John  F.  Pope  to  make  a  survey  and 
report  on  the  practicability  of  the  project.  Mr.  Pope,  after  an  examination  and  in- 
vestigation, reported  in  favor  of  such  a  project  and  his  report  was  referred  to  a  Com- 
mittee composed  of  Mr.  John  McDonald  and  Captain  W.  C.  Walsh,  who  reviewed 
it  and  submitted  estimates  of  the  cost  of  construction.  The  feasibility  of  the  project 
was  urged  by  Mr.  Wooldridge  and  Mr.  John  McDonald,  the  latter  running  for 
Mayor  in  the  fall  of  1899  on  that  issue  and  being  elected  by  a  large  majority,  to- 
gether with  a  Board  of  Aldermen  favorable  to  the  enterprise. 

BEGINNING  OF  ACTIVE  WORK 

In  February  1890,  an  appropriation  was  made  for  an  investigation  of  this  pro- 
ject, and  Mr.  Jos.  P.  Frizell,  a  hydraulic  engineer  of  Boston,  was  employed  for  this 
purpose.  On  March  26,  1890,  Mr.  Frizell  submitted  a  report  recommending  the  con- 
struction of  a  60-foot  masonry  dam. 


Beginning  of  Active  Work.  41 

There  were  practically  no  hydrographic  data  of  the  stream  flow  of  the  Colorado 
Eiver  available  at  that  time.  The  recollection  of  the  oldest  inhabitant  established 
an  extreme  flood  height  above  low  water  in  the  river,  of  45  feet,  which  Mr.  Frizell  es- 
timated as  probably  equal  to  250,000  cubic  feet  per  second  and  which  he  found  would 
produce  a  depth  of  16  feet  on  the  crest  of  the  proposed  dam.  Mr.  Frizell  assumed 
that  the  flow  of  the  Colorado  Eiver  was : 

'  *  Wholly  maintained  by  springs,  issuing  from  cavities  in  the  rock  and  is  un- 
affected by  current  rainfall  until  the  latter  becomes  sufficient  to  cause  a  flow  from 
the  ground.  This  is  the  present  condition  and  I  conclude  we  shall  not  be  far 
wrong  in  taking  the  present  flow  of  the  stream  as  the  quantity  that  can  be  de- 
pended upon.  This,  as  I  have  ascertained  by  careful  measurements,  is  nearly 
1000  cubic  feet  per  second.  There  will  no  doubt  be  times  during  the  hottest 
weather  when  the  water  will  fall  below  this  stage  on  account  of  increased  eva- 
poration. I  am  told  however  that  a  month  very  rarely  passes  without  rains  in 
some  part  of  the  drainage  basin  sufficient  to  cause  a  slight  rise  at  Austin. 

"The  great  extent  of  the  pond  will  enable  a  considerable  deficiency  in  the 
flow  of  the  stream  to  be  made  good  by  storage.  From  the  best  information  I  can 
obtain,  the  pond  will  extend  some  30  to  35  miles  from  the  dam,  with  an  average 
width  of  14  of  a  mile,  containing  a  water  surface  of  some  8  square  miles  and  a 
total  volume  of  something  like  2,800,000,000  cubic  feet  of  water.  Should  the 
flow  of  the  stream  diminish  to  y2  of  the  above  quantity,  a  single  foot  in  depth  on 
the  pond  will  make  good  the  deficiency  for  a  period  of  five  days,  and  6  feet  will 
make  it  good  for  thirty  days. ' ' 

Mr.  Frizell  also  calls  attention  to  the  possible  use  of  4-foot  flashboards  for  addi- 
tional storage,  estimates  the  average  working  head  from  the  proposed  dam  at  57^ 
feet,  and  calculates  that  at  80  per  cent,  efficiency  5,227  HP  could  be  delivered  contin- 
uously. On  the  basis  of  concentrating  the  entire  weekly  flow  of  the  stream  into  a 
working  week  of  60  hours,  he  calculated  the  available  power  at  14,656  HP.  His  es- 
timate of  the  cost  of  the  entire  endeavor,  including  the  dam,  power  house,  water  works 
system,  electric  light  system  and  equipment,  was  $1,362,781.  The  general  scheme 
was  approved  by  Mr.  John  Bogart,  Consulting  Engineer  of  New  York. 

Soon  after  the  submission  of  this  report,  an  engineering  party  surveyed  the 
flowage  above  the  proposed  dam  site  and  determined  that  the  pond  would  extend 
22  miles  above  the  dam.  Bids  for  the  proposed  issue  of  bonds  and  for  the  construc- 
tion of  the  dam  were  received  on  October  15,  1890,  and  the  bid  of  Mr.  Bernard  Cor- 
rigan,  of  $501,151 — being  the  lowest  for  the  construction  of  the  dam  and  the  excava- 
tion of  the  canal — was  accepted,  and  a  contract  was  duly  entered  into. 

Excavation  for  the  foundation  of  the  dam  began  on  November  5,  1890,  and  the 
first  stone  was  laid  in  the  dam  on  May  5,  1891.  The  work  was  delayed  to  some  ex- 
tent by  the  floods  of  the  river,  but  the  last  stone  in  the  dam  was  laid  on  May  2,  1893. 
The  upper  and  lower  faces  and  the  dam  crest  were  of  red  granite  from  Granite  Moun- 
tain. The  interior  of  the  dam  was  of  the  hardest  local  limestone  rubble.  All  mas- 


42 


Report  on  the  Dam  at  Austin,  Texas. 


onry  was  laid  in  Portland  cement.     The  total  amount  paid  to  Mr.  Corrigan,  under 
his  contract,  including  extras,  was  $627,927.90. 

The  general  scheme  of  development  as  planned  by  Mr.  Frizell,  is  shown  in  Fig. 
13. 

CHANGE  IN  PLANS 

Early  in  the  year  1892,  a  serious  difference  of  opinion  arose  between  some  of 
the  Board  of  Public  Works  and  Mr.  Frizell,  concerning  the  location  of  the  power 
house  (which  Mr.  Frizell  had  planned  to  place  some  600  feet  below  the  dam)  and 
the  method  of  conducting  the  water  to  the  power  house,  which  Mr.  Frizell  had  pro- 
posed to  accomplish  through  an  open  canal.  The  Board  was  of  the  opinion  that  a 


Hews. 

FIGUKE  13 — Plan,  Profile  and  Cross  Section  of  Austin  Dam  as  Originally  Designed.    J.  P.  Frizell,  En- 
gineer; John  Bogart,  Consulting  Engineer.  (Eng.  News,  July  11,  1891.) 

safer  location  would  be  on  the  rock  ledge  below  the  dam,  and  that  the  water  should 
be  conducted  to  the  power  house  by  iron  penstocks  instead  of  through  an  open  canal. 

In  January,  1892,  Mr.  E.  C.  Geyelin  was  employed  to  report  on  this  matter.  His 
report  was  made  on  February  17,  1892,  and  the  changes  in  plans  suggested  were 
advised.  These  changes  were  opposed  by  Mr.  Frizell,  and  the  Board  finally  em- 
ployed Mr.  J.  T.  Fanning  of  Minneapolis  to  pass  on  these  matters.  On  June  24,  Mr. 
Fanning  submitted  his  report,  recommending  the  change  in  the  location  of  the  power 
house  and  the  use  of  penstocks  instead  of  an  open  canal.  He  also  advised  a  change  in 
the  form  of  the  crest  of  the  dam  to  that  shown  in  Fig.  19,  page  49. 

Mr.  Fanning  was  retained  as  Consulting,  and  Mr.  Frizell  resigned  his  position  as 
Chief  Engineer  on  June  30,  1892.  Mr.  E.  W.  Groves,  who  had  been  Assistant  Engi- 
neer to  Mr.  Frizell  since  the  work  started,  was  appointed  Engineer  in  Charge  of  Con- 
struction of  the  Dam.  At  this  time  the  foundation  was  in  place  and  the  masonry  work 
above  in  progress. 


Change  in  Plans. 


43 


The  dam  was  built  on  the  rock  bed  of  an  ancient  and  greater  river  than  the  present 
Colorado.  The  shores  of  the  ancient  stream  were  rock  and  nearly  vertical.  The  mod- 
ern Colorado  occupied  less  than  half  of  the  ancient  rock  channel  at  this  point,  and  the 
remainder  of  the  old  channel,  including  more  than  its  east  half,  was  filled  with  an  al- 
luvial deposit  40  feet  or  more  in  depth.  A  narrow  cut  was  made  through  this  deposit 


r»C!i.rr»mc.  RECORD 


FIGURE  14— A.  Plan  of  Original  Penstocks  and  Power  House,  J.  T.  Fanning  Consulting  Engineer. 

(Bng.  News  Jan.  26,  1893.) 


B.  Section  of  Original  Power  House,  J.    T.   Fanning,   Consulting   Engineer. 
(Eng.  Rec.  July  1,  1983.) 


44  Report  on  the  Dam  at  Austin,  Texas. 

to  the  east  shore  for  the  purpose  of  construction  of  the  foundation  of  the  dam.     (See 
Fig.  15,  page  45,  also  Fig.  16,  page  45.) 

Mr.  Groves  stated  (see  Engineering  News  May  3,  1900,  page  290)  that  the  rock 
was  good  for  about  150  feet  from  the  east  bluff  at  which  point  a  fault  was  encountered 
which  extended  about  75  feet.  The  rock,  however,  was  found  to  be  poor  for  about  350 
feet  farther,  when  it  began  to  improve,  and  under  the  west  portion  of  the  dam  the 
rock  was  good.  He  further  says : 

' '  In  the  fault  there  is  no  semblance  of  stratified  rock  except  occasionally  a  de- 
tached piece.  Most  of  the  material  was  adobe  or  pulverized  rock  with  an  occa- 
sional streak  of  red  clay.  The  excavation  at  this  place  *  :  *  was  carried  down 
8  to  10  feet  in  the  upstream  trench,  and  the  trench  widened  to  10  feet  or  15  feet, 
the  fault  extending  down  indefinitely. ' ' 

The  foundation  was  not  only  poor,  but  the  conditions  evidently  made  proper  work 
difficult.  Mr.  Groves  (see  Eng.  News,  Jan.  26,  1893,  page  87)  described  the  founda- 
tion work  as  follows : 

"During  the  laying  of  the  foundation  considerable  water  was  encountered, 
the  excavation  in  places  being  carried  11  feet  below  low  water  in  the  river  to  get 
to  solid  rock.  Two  6"  discharge  centrifugal  pumps  were  used  to  keep  the  foun- 
dation dry,  but  in  places  where  it  was  impossible  to  get  to  the  bottom  of  the 
trench  in  good  condition  to  bed  stone  properly,  concrete  was  used  to  lead  up  above 
the  water.  Strong  flowing  springs  were  encountered  in  various  parts  of  the 
foundation  which  gave  considerable  trouble  until  wrought  iron  pipes  were  made 
use  of.  The  water  from  the  springs  was  conducted  to  the  pumps  through  pipes 
of  suitable  size,  the  pipes  being  covered  with  masonry,  and  the  springs  sur- 
rounded by  a  wall  of  masonry  well  built.  After  the  mortar  had  thoroughly  set, 
this  wall  would  be  filled  with  rich  concrete  and  no  more  trouble  would  be  exper- 
ienced from  that  spring.  The  end  of  the  pipe  was  stopped  with  a  plug  or  iron 
cap. ' ' 

DATA  OF  THE  COMPLETED  DAM 

The  data  for  the  dam  as  completed  were  summarized  by  Mr.  E.  W.  Groves,  As- 
sistant Engineer,  as  follows: 

Length  of  Spillway 1,125  ft. 

Length  of  Dam,  including  Bulkhead 1,275  ft. 

Height  above  Low  Water 60  ft. 

Maximum  height  above  Foundation 68  ft. 

Width  of  Base 66  ft. 

Power  Available  (60  hrs.  per  week) 14,500  HP 

Minimum  Flow  1,000  cu.  ft.  sec. 

Maximum  Flow 250,000  cu.  ft.  sec. 

Drainage  Area  above  Dam 50,000  sq.  mi.   • 

Length  of  Lake  formed 25  miles 

Area  of  Lake 2,000  acres 


Construction   of  Original  Dam.  45 


FIGURE  15 — Construction  of  Original  Dam  at  Austin,  Texas,  Showing  Narrow  Trenches  on  the  East  Side 
of  the  River,  in  which  the  Dam  was  Constructed.      (Bng.  News  Jan.  26,  1893.) 


FIGURE  16 — Headgate  Masonry  in  Process  of  Construction  at  East  End  of  Dam,  Jan.  4,  1893.     Also  show- 
ing Narrow  Trench  in  which  Dam  was  Constructed.     (Eng.  News  Jan.  26,  1893.) 


46 


"  »  ';£  ^2$"°*,**Jo     ,"  o*   * 

Report  on  the  Dam   at  Austin,   Texas. 


FIGURE   17 — Break   under   Headgates,   Austin,   Texas  May   30,   1893.     (Eng. 

News  July  27,  1893.) 

M  L 


H 
SECTION  X-Y 


FIGURE  18— Plan  and  Section  Showing  Leaks  at  Austin  Dam  prior  to  1900.     (Eng. 

News  Feb.  22,  1900.) 


Leaks  in  the  Foundation.  47 


Masonry  in  Dam 95,000  cu.  yds. 

Minimum  Size  of  Granite  used 93.5  cu.  ft. 

DEVELOPMENT  or  LEAKS  IN  THE  FOUNDATION 

The  weakness  of  the  east  portion  of  the  foundation  was  recognized  and  clay  was 
dumped  against  the  upstream  face  to  prevent  the  seepage  of  water  under  the  struc- 
ture. Soon  after  the  dam  was  completed,  springs  were  discovered  just  below  the  toe 
and  opposite  the  weak  portion  of  the  foundation.  (See  letter  from  E.  W.  Groves, 
Eng.  News,  May  3,  1900,  page  290.) 

On  September  2,  1892,  a  contract  was  entered  into  with  Mr.  James  Waterson 
for  the  construction  of  the  head  gate  masonry,  and  this  work  was  finished  on  May  12, 
1893. 

On  January  20,  1893,  a  contract  was  made  with  Waterson  &  Wattinger  for 
building  the  power  house  foundations.  This  work  was  completed  the  following 
March.  On  the  30th  of  May,  1893,  a  break  occurred  about  75  feet  above  the  head 
gate  masonry  and  the  water  passed  down  to  a  depth  of  about  25  feet  below  the  mas- 
onry and  out  through  a  soft  stratum  of  rock  into  the  excavation  of  the  power  house, 
causing  a  portion  of  the  head  gate  masonry  to  settle,  and  overturning  a  part  of  the 
power  house  foundation.  (See  Fig.  17,  page  46.) 

The  cause  of  this  break  was  a  layer  of  loose  material  in  the  rock  below  the  foun- 
dation of  the  head  gate  masonry.  As  the  water  was  raised  in  the  pond  above  the 
dam,  it  found  access  to  this  seam  and  washed  out  the  sand  or  clay  which  it  contained, 
causing  a  settlement  of  the  foundation. 

The  head  gate  masonry  cracked  about  40  feet  from  the  end  of  the  dam  along  the 
line  H  M,  shown  in  Fig.  18,  page  46,  and  settled.  The  earth  east  of  the  east  end  of 
the  head  gates  settled  for  a  distance  of  25  feet.  A  cofferdam  was  built  from  the 
east  end  of  the  dam  to  the  river  bank,  about  125  feet  above  the  head  gate  masonry, 
and  the  flow  of  the  water  thus  stopped.  The  broken  part  of  the  head  gate  masonry 
was  removed,  leaving  only  that  portion  over  penstocks  1  and  2 ;  and  an  excavation 
nearly  200  feet  long  and  70  feet  deep,  with  an  average  width  of  7  feet,  was  made. 
This  trench  reached  to  a  level  of  57  feet  below  the  crest  of  the  dam  or  within  3  feet 
of  the  level  of  the  toe.  The  head  gate  masonry  was  rebuilt,  the  excavation  beyond 
the  penstocks  being  filled  by  a  concrete  wall  112  feet  long  which  was  8  feet  thick  for 
the  90  feet  next  to  the  head  gates,  and  5  feet  thick  for  the  rest  of  the  distance. 

In  excavating  for  this  extension  wall,  alternate  layers  of  hard  and  soft  limestone 
were  encountered.  The  bottom  layer  of  the  concrete  filling  was  laid  on  one  of  these 
layers  of  strata,  but  it  was  fully  demonstrated  that  a  current  of  water  was  running 
underneath.  Several  holes  were  drilled  in  which  the  water  rose  in  jets  several  in- 
ches high ;  however,  it  was  thought  safe  to  plug  these  holes  and  to  ignore  the  stream 
below.  (See  Bui.  164,  Univ.  of  Texas,  by  T.  U.  Taylor,  page  31.) 


48  Report  on  the  Dam  at  Austin,  Texas. 

The  bulkhead  masonry  originally  extended  to  the  level  RS  (see  Fig.  18,  page 
46)  or  36  feet  below  the  top  of  the  dam;  but  as  an  extra  precaution  a  tunnel  ESTU,  6 
feet  square  and  60  feet  long,  was  cut  under  the  bulkhead  masonry  back  to  the  end 
of  the  dam  proper,  and  this  space  was  filled  with  concrete.  The  space  below  the  42 
foot  level  under  the  tunnel  was  not  disturbed. 

Apparently  there  had  been  considerable  interference  by  the  Mayor,  who  was  also 
Chairman  of  the  Board  of  Public  Works,  with  the  plans  of  the  Engineers  both  before 
and  after  the  resignation  of  Mr.  Frizell.  Both  the  Resident  Engineer,  Mr.  Weren- 
skold,  and  the  Contractor  for  the  head  gates,  Mr.  Waterson,  had  been  ordered  (in 
Nov.  1892)  by  the  Board  to  follow  the  instructions  of  the  Mayor  (see  Eng.  News, 
June  29,  1893,  p.  619),  and  this  constant  interference  led  to  the  resignation  of  the 
Engineer  in  Charge,  Mr.  E.  W.  Groves,  in  the  spring  of  1893.  (See  Eng.  News, 
July  27,  1893,  p.  78).  This  interference  seems  from  the  evidence  to  have  been  large- 
ly accountable  for  the  imperfect  work  at  the  head  gates. 

After  the  completion  of  the  new  headworks,  the  foundation  for  the  power  house 
was  excavated  to  a  depth  of  more  than  80  feet  below  the  crest  of  the  dam.  Due  to 
the  excess  of  water  encountered,  the  original  contractors  threw  up  the  work,  and  the 
new  contractors  succeeded  in  controlling  the  flow  of  water  through  the  rock  by  con- 
structing a  cement  chamber  at  D  (see  Fig.  18,  page  46)  with  a  10"  horizontal  pipe 
outlet  which  projects  through  the  wall  of  the  power  house  at  the  point  C,  about  54 
feet  south  of  the  crest  of  the  dam.  (See  also  Fig.  21,  page  51.) 

This  water  undoubtedly  flowed  under  the  head  gate  foundation,  coming  indi- 
rectly from  the  lake  above  the  dam.  Measurements  taken  in  October,  1895,  showed 
a  discharge  from  this  pipe  of  4.6  cubic  feet  per  second. 

WAKNINGS  OF  DISASTEK 

On  April  8,  1896,  Mr.  J.  P.  Frizell  wrote  Mayor  Hancock  of  Austin,  in  part  as 
follows  (see  Eng.  News.  Apr.  1900,  p.  252) : 

' '  In  laying  the  foundation  of  the  dam  at  Austin,  a  very  friable  foundation  of 
rock  was  met  with  some  300  or  400  feet  from  the  eastern  end ;  in  fact,  the  rock  was 
poor  for  the  entire  easterly  half  of  the  dam.  I  was  apprehensive  that  danger- 
ous abrasion  might  occur  here  in  future,  but  as  this  part  at  the  time  was  over- 
hung by  a  bank  of  earth  40  or  50  feet  high,  my  plan  was  to  wait  until  the  bank 
had  disappeared,  as  it  might  be  expected  to  do  on  completion  of  the  dam,  and  then 
to  execute  some  supplementary  work  of  protection.  *  : 

"My  purpose  in  writing  is  to  suggest  that  you  cause  soundings  to  be  made 
along  the  toe  of  the  dam  to  ascertain  if  dangerous  abrasion  is  in  progress  in  that 
locality." 

In  1897,  Mr.  G.  H.  Palm  of  Austin,  while  fishing  along  the  toe  of  the  dam  ran  his 
fishing  pole  under  the  toe  for  a  distance  of  6  feet,  showing  conclusively  that  undermin- 
ing had  occurred  over  the  weak  strata  where  the  dam  finally  gave  way.  (See  B  Fig.  19, 
page  49.) 


Silting  of  the  Reservoir. 


49 


In  1899  a  leak  was  also  discovered  at  the  point  A  (Fig.  18,  page  46),  near  the  east 
end  of  the  dam,  and  was  stopped  by  filling  behind  the  dam  at  this  point  with  clay, 
loose  and  in  bags.  While  this  filling  was  in  progress,  the  water  discharging  from  the 
10"  pipe  almost  ceased  for  a  few  hours,  but  soon  reached  its  normal  amount,  being 
kept  muddy  while  the  fill  was  in  progress. 

In  the  fall  of  1899,  water  was  noted  disappearing  at  a  point  B  (see  Fig.  18,  page 
46)  only  a  few  feet  from  the  shore.  A  cofferdam  was  constructed  around  this  point 


A.  B. 

FIGURE  19 — Sections  of  Austin   Dam.     (A)  as  Constructed  upon  Recommendations  of 

J.   T.    Fanning.     (B)   Showing   Supposed   Condition   of   Undercutting   and    Silt 

Deposit  prior  to  Failure  in  1900.     (Eng.  News  May  10,  1900.) 

and  afterwards  filled  with  some  difficulty  with  hay  and  earth.     The   location  and 
method  by  which  these  latter  two  leaks  were  remedied  are  shown  in  Fig.  22,  page  51. 

THE  SILTING  OF  THE  RESERVOIR 

In  Water  Supply  and  Irrigation  Paper  No.  40  on  "The  Austin  Dam,"  Professor 
T.  U.  Taylor  states  that  in  1890,  cross  sections  of  the  Colorado  River  were  taken  at 
sixteen  stations  above  the  dam  site.  Cross  sections  were  again  taken  by  the  United 
States  Geological  Survey  in  May,  1897  and  in  January,  1900.  These  sections  and  the 
silt  deposit  that  had  occurred  between  these  dates  at  the  various  stations  are  shown 
in  the  diagrams  on  page  50.  Between  May  16, 1893,  when  the  water  first  flowed  over 
the  dam,  and  May,  1897,  31,667,000  cubic  yards  of  silt,  occupying  38  per  cent,  of  the 
original  reservoir  capacity,  had  been  deposited.  In  January,  1900,  this  amount  had 
been  increased  by  8,429,000  cubic  yards,  the  total  silt  deposit  then  occupying  48  per 
cent,  of  the  required  reservoir  volume.  In  January,  1900,  fhe  silt  immediately  above 
the  dam  had  reached  a  depth  of  28  feet  or  a  level  38  feet  below  the  crest  of  the  dam 
(see  B  Fig.  19).  Concerning  the  nature  of  the  silt,  Professor  Taylor  says: 

"In  1897  this  silt,  to  within  two  miles  of  the  head  of  the  lake,  was  a  fine,  im- 
palpable, absolutely  gritless  deposit,  and  where  newly  exposed  would  not  bear  an 
appreciable  weight  on  its  surface.  The  writer  has  often  tried  its  resistance  all 
along  the  lake,  and  an  oar  could  be  driven  into  it  several  feet  with  moderate  pres- 


50 


Report  on  the  Dam  at  Austin,  Texas. 


LOCALITY 


D/STANCE 
FRO 

DAM 


CLIFTON 
HARRISONS  Bff 
HO  HEY  CREEK 

HUGHES 

SANTA  MONICA 
SCOTT'S  TOWER 

MCNEILLS  LANE 

OGOfflTA 
DEVILS  HOLLOW 

ENNIS  FARM 


BULL  CREEK 


DRY  CREEH 


MORMON  FALLS 


500 


460 


650 


~''"<"f-ffffff-£s+*' 


76O 


7QO 


950 


680 


//BO 


/300 


I7.4O  " 
/S30  " 
I4-.60  " 

/3.7C  " 
IQ.4O  " 

5.25  " 
775  " 

TOO  " 
5.60  " 
4.0O  " 
2.00  " 


I.ZO  " 


0.20  " 


FIGUBE  20 — Cross  Sections  of  Lake  above  Austin  Dam  showing  Accumulation  of  Sedi- 
ment between  1893  and  1897  (Lower  Shaded  Area)   and  between  1897  and  1900 
(Upper  Shaded  Area).     Numbers  above  Sections  indicate  Length  in  Feet 
(Water  Supply  Paper  No.  40  U.  S.  G.  S.) 


Leaks   in  the  Foundation. 


51 


FJGUBE   21 — Leak   under   Headgates   Discharging   through    10-Inch   Pipe   in   Foundation 
Wall  prior  to  1900.     (Water  Supply  Paper  No.  40. U.  S.  G.  S.) 


FIGURE  22 — Showing  Location  of,  and  Methods  used  to  stop  Leaks  above  Austin  Dam 
prior  to  1900.      (Water  Supply  Paper  No.  40  U.  S.  G.  S.) 


52 


t  on   the  Dam  at  Austin,   Texas. 


FIGURE  23 — Dam  and  Power  Hou^e  at  Austin,  Texas,  prior  to  1900.     (Note  Detritus 

below  Dam.) 


FIGURE  24 — Plan  Showing  Break  in  Original  Austin  Dam  April  7,  1900.     Eng.  News 

Apr.  19,  1900.) 


The   1900  Failure.  53 

sure.     Shovelfuls  of  it  placed  upon  boards  in  a  heaped-up  mess  would  immedi- 
ately settle  and  spread  so  that  the  upper  surface  was  almost  horizontal. ' ' 

It  is  evident  from  the  above  that  the  silt  under  water  and  in  contact  with  the  dam 
must  have  exerted  a  considerable  extra  pressure  against  that  structure. 

THE  1900  FAILURE 

These  various  indications  of  weakness  seemingly  led  to  only  temporary  measures 
of  repair  and  apparently  no  general  investigation  was  made  or  radical  betterments  at- 
tempted. The  rock  below  the  eastern  portion  of  the  dam  was  covered  with  alluvium 
during  the  construction  of  the  dam,  and  this  was  washed  away  by  the  occasional  floods 
of  the  river  after  the  dam  was  completed.  The  rock  had  therefore  never  been  examined 
nor  its  condition  ascertained.  It  was  apparently,  however,  of  the  same  friable  nature 
as  that  in  the  foundation  of  the  dam  as  described  above.  On  this  soft  deposit  was  ex- 
pended the  energy  generated  by  the  falling  waters  of  the  passing  floods.  While  the 
change  in  the  cross  section  of  the  dam  was  undoubtedly  an  improvement  in  the  con- 
dition of  hydraulic  flow,  yet  the  toe  of  the  dam  was  too  short  to  give  flood  flows  a  hori- 
zontal direction,  and  the  tremendous  energy  developed  by  the  falling  waters  (amount- 
ing to  about  360,000  HP  in  the  flood  of  1900)  was  partially  expended  in  tearing  up 
and  displacing  these  rocks  and  depositing  them  on  a  bar  below  (see  Fig.  23,  page  52), 
or  washing  them  away ;  at  the  same  time  the  back  current  was  undermining  the  struc- 
ture itself  (see  B  Fig.  19,  page  49).  The  discharge  of  the  waters  from  the  wheels  along 
the  toe  of  the  dam  developed  velocities  altogether  too  low  to  have  had  any  serious  ef- 
fect in  eroding  this  rock,  but  the  cross  currents  produced  at  times  of  flood  by  the  pres- 
ence of  the  alluvial  deposits  in  the  old  river  channel  below  the  eastern  portion  of  the 
dam,  may  have  added  seriously  to  the  erosion. 

On  April  7, 1900,  with  the  water  11  feet  above  the  crest  of  the  dam,  the  dam  gave 
way  at  B  (see  Fig.  24,  page  52)  about  300  feet  from  the  east  end,  and  two  sections,  AB 
and  BC,  each  about  250  feet  long  were  shoved  downstream  a  distance  slightly  greater 
than  the  width  of  the  dam,  into  positions  A'B'  and  B'C'.  There  was  no  overturning  of 
the  structure  which  held  its  section  for  some  time  after  the  break.  The  section  B'C' 
finally  disintegrated,  falling  upstream,  and  the  eastern  end  of  the  section  A'B'  was 
soon  after  broken  up  and  disappeared.  The  water  from  the  dam  broke  through  the 
windows  of  the  power  house,  and  later  on  the  recession  of  the  flood  caused  the 
north  end  of  the  power  house  walls  to  fall  outward,  taking  with  them  the  roof  over  the 
dynamo  room  and  wrecking  the  corresponding  part  of  the  east  wall. 

INVESTIGATIONS  AND  BEPORTS  MADE  AFTER  THE  1900  FAILURE 

After  the  destruction  of  the  dam  various  investigations  and  reports  were  made, 
and  various  projects  considered  for  its  reconstruction.  On  June  9,  1900,  Professor 
T.  U.  Taylor  of  the  University  of  Texas,  made  soundings,  and  ascertained  the  founda- 
tion course  of  the  dam  and  several  feet  of  the  underlying  rock  has  been  washed  out 
by  the  1900  flood.  (See  Eng.  News,  Dec.  6, 1900,  p.  390). 


54 


Report  on  the  Dam  at  Austin,  Texas. 


Later,  an  estimate  on  reconstruction  was  made  by  Mr.  W.  F.  Foster  to  the  City 
Government.  This  was  followed,  in  1905,  by  a  report  by  Mr.  Geo.  E.  Evans  of 
Boston  for  the  firm  of  Stone  and  Webster. 


FIGUBE  25 — Location  of  Borings  Made  in  1907. 


'ast_Portidn West  Portion  oTDam. 


FL  Ffinf 
L&- Lime-stone 

/lard Limestone 
3L5.  Soft  Limestone 
CHLS.  Ctia/ty  Limestone 
Cfiv.    Cavities 

0  20  40  60  iO  100  100 


ca/  ScaJe  -FECT- Horizontal  Scale 

FIGURE  26 — Rock  Sections  as  Disclosed  by  Borings  of  1907. 

In  1907,  the  Consolidated  Construction  Company  was  granted  a  franchise  by  the 
City  Council  to  reconstruct  and  maintain  a  dam  at  or  near  the  old  site,  to  be  paid 
for  in  40  annual  installments.  Mr.  Walter  G.  Kirkpatrick  was  retained  and  reported, 
in  1908,  to  the  Water  and  Light  Commission  on  the  rebuilding  of  the  dam.  Under 
Mr.  Kirkpatrick 's  direction,  26  borings  were  made  of  the  dam  site  under  the  imme- 
diate direction  of  Mr.  A.  C.  Blanton.  The  locations  of  these  borings  are  shown  on 


Investigations  after  the   1900  Failure.  55 

Fig.  25,  and  their  depth  and  the  general  information  disclosed  are  shown  in  Fig.  26, 
page  54.     Of  these  borings  Mr.  Blanton  says: 

"The  stratification  disclosed  by  the  core  borings  was  of  alternate  moder- 
ately hard  limestone,  soft  adobe  and  cavities." 

These  borings,  he  further  states : 

11   :        *  demonstrated  indisputably  the  very  undesirable  condition  existing 
at  the  site."    See  Eng.  News,  Apr.  22, 1915,  page  78.) 

On  account  of  the  conditions  developed,  Mayor  Maddox  refused  to  sign  the  fran- 
chise ordinance  of  the  Consolidated  Construction  Company,  and  arranged  for  a  re- 
port by  a  Board  of  Engineers,  consisting  of  Arthur  P.  Davis,  Chief  Engineer  of  the 
United  States  Reclamation  Service,  Louis  C.  Hill  of  the  Reclamation  Service,  and 
Professor  T.  U.  Taylor  of  the  Engineering  Department  of  the  University  of  Texas. 
This  Board,  with  the  assistance  of  Dr.  F.  W.  Simons,  Professor  of  Geology  in  the 
University  of  Texas,  inspected  the  series  of  borings  above  described,  considered  the 
geological  formations  both  at  the  dam  and  at  Mt.  Bonnel,  and  recommended  the  con- 
struction of  a  new  dam  at  Mt.  Bonnel  rather  than  at  the  old  site,  provided  borings 
showed  formations  as  favorable  as  surface  conditions  seemed  to  indicate.  If,  how- 
ever, the  City  decided  to  rebuild  at  the  site  of  the  old  dam,  this  Board  advised : 

1st.  That  a  deep  curtain  wall  be  constructed  near  the  upstream  face  of  the  dam 
to  cut  off  percolation  under  the  dam  so  far  as  possible  in  order  to  reduce  upward 
pressure  to  the  minimum.  This  curtain  wall  they  advised  should  be  six  feet  in  thick- 
ness and  be  connected  by  steel  rods  to  the  main  dam.  It  should  be  carried  to  depths 
to  be  determined  by  local  conditions  as  the  work  proceeded,  but  in  general  to  a  depth 
of  20  to  30  feet  below  the  original  foot  of  the  dam  and  below  any  cavities  disclosed 
by  borings  or  otherwise. 

2d.  They  further  advised  the  increase  in  the  mass  of  the  dam  in  order  to  in- 
crease its  resistance  to  sliding,  the  increase  to  be  so  located  as  to  utilize  the  pressure 
of  water  on  the  dam  so  far  as  possible. 

3d.  They  further  advised  that  the  foundation  at  the  toe  of  the  dam  should  be  re- 
paired and  extended  by  monolithic  reinforced  concrete  to  add  to  the  resistance  to 
sliding  and  to  protect  the  toe  from  further  erosion. 

4th.  They  further  advised  the  entire  reconstruction  of  the  east  abutment  and 
bulkhead  walls,  and  that  the  body  of  the  main  portion  of  the  dam  which  was  to  be  re- 
placed should  be  built  of  concrete  with  granite  facing  on  its  lower  slope  and  about 
10  feet  below  the  crest  on  the  back  of  the  dam. 

The  cross  sections  proposed  by  this  Board  are  shown  in  Fig.  27,  page  56. 

On  April  5,  1910,  the  City  Council  was  authorized  by  a  vote  of  the  citizens  of 
Austin  to  make  a  contract  with  Dumont-Holmes  Steel  Concrete  Company  to  erect  and 
maintain  a  dam  65  feet  high  above  low  water  at  the  old  site,  which  contract  expired  by 
limitation  on  January  23,  1911. 


56 


Report  on  the  Dam   at  Austin,  Texas. 


THE  JOHNSON  CONTRACT 

On  September  11, 1911,  a  franchise  was  granted  to  William  D.  Johnson  which  pro- 
vided for  the  construction  of  a  dam  and  power  plant  under  conditions  which  are  con- 
sidered in  considerable  detail  in  Appendix  2. 


-  eefvf/es  TO  EXIST/MS  Poerjotj  OP  OHM 


110    /60     ISO   I4O    /JO     no     I/O     100     90     SO      70      60     SO     40     JO      20       10       0 


90 
SO 
70 

to 

so 

40 
30 
20 
IO 


New  DGM  IH  BROKEN  SFCTION 


-    SECTION  or* Peoooseo 

QlTE 


FIGURE  27 — Cross  Sections  for  the  Austin  Dam  as  Proposed  by  Messrs,  Davis,  Hill 

and  Taylor,  1908. 


APPENDIX  2 

CONTBACT  OF  WlLLIAM  D.  JOHNSON  AND  ASSIGNS  FOE  THE  RECONSTRUCTION  OF  AUSTIN 

DAM  AND  POWEB  PLANT 

As  the  purpose  of  this  Report  is  an  investigation  of  the  reconstruction  of  the  dam 
and  power  house  under  the  above  contract,  and  a  determination  of  any  changes  that 
have  been  made  from  the  requirements  thereof,  it  becomes  necessary  to  consider  the 
ordinance,  specifications  and  plans,  which  together  constitute  this  contract. 

FRANCHISE  ORDINANCE 

The  ordinance  is  a  document  of  some  24  sections,  couched  in  the  usual  legal 
phraseology  and  which,  for  the  purpose  of  a  clear  understanding,  is  here  abstracted  as 
follows : 

Section  1.  William  D.  Johnson  and  his  assigns  are  granted  the  right  and  fran- 
chise to  erect  a  dam  across  the  Colorado  River  at  or  near  the  location  of  the  former 
dam.  Such  grant  is  for  a  period  of  two  years  for  the  purpose  of  construction,  with 
such  extensions  as  are  made  necessary  by  conditions  beyond  control,  and  for  the  ad- 
ditional period  of  25  years  from  the  date  of  completion. 

Section  2.  Provides  that  Johnson  shall  have  the  use  of  all  poles,  wires  and  equip- 
ment on  the  lines  between  the  original  dam  and  the  City  power  house,  and  all  mater- 
ial contained  in  the  original  dam  adjacent  to  the  power  house,  for  use  in  construction ; 
none  of  this  material  can  be  sold,  however,  until  $25,000  has  been  expended  on  con- 
struction work. 

Section  3.  The  City  of  Austin  leases,  transfers  and  delivers  to  the  said  Johnson 
during  the  life  of  the  ordinance  all  materials  in  the  dam,  headgates  and  power  house, 
and  all  of  its  rights,  titles  and  interest  in  the  lands  occupied  by  these  structures,  and 
all  land  owned  by  the  City  adjacent  to  the  dam  and  downstream  from  a  line  20  feet  up- 
stream from  the  crest  of  the  dam,  together  with  all  necessary  flowage  rights. 

Section  4.  Grants  Johnson  the  privilege  to  assign  his  rights  to  any  person,  firm 
or  corporation,  and  the  right  to  pledge,  mortgage  and  assign  to  any  trustee  all  of  the 
rights,  power  and  franchise  granted. 

Section  5.  Provides  that  Johnson  shall  indemnify  the  City  of  Austin  against  any 
damage  to  the  property  of  the  City  and  to  hold  the  City  harmless  from  any  damage 
occasioned  by  any  act  or  negligence  of  Johnson,  his  assigns  or  agents. 

Section  6.  Provides  that  Johnson  shall  construct  a  dam,  at  or  near  the  site  of  the 
dam  formerly  constructed  by  the  City  of  Austin,  in  strict  compliance  with  certain 
plans  and  specifications ;  the  said  dam  shall  be  five  feet  higher  than  the  crest  of  the 
original  dam  and  shall  be  fully  equipped  in  accordance  with  said  plans  and  specifica- 


58  Report  on  the  Dam  at  Austin,  Texas. 

tions.     The  equipment  shall  include  headgate  masonry,  head  gates,  forebay  racks, 
flumes,  turbines,  draft  tubes,  and  tail  race. 

The  said  Johnson  shall  further  supply  the  equipment  of  the  power  house,  which 
shall  include  three  vertical  turbines  of  not  less  than  2400  horse  power  each  when  op- 
erating under  a  head  of  sixty  feet ;  three  6600  volts,  3-phase,  60-cycle  electric  genera- 
tors, to  be  directly  connected  to  said  three  2400  HP  vertical  turbines,  and  capable  of 
generating  not  less  than  6000  HP  of  electrical  energy;  two  direct  current  exciting 
generators  of  such  capacity  that  either  one  shall  be  able  to  furnish  the  necessary  full 
load  exciting  current  for  all  three  of  the  3-phase  generators;  two  electric  pumps, 
each  of  which,  when  pumps  are  working  together,  shall  be  capable  of  delivering 
6,000,000  gallons  of  water  per  day  of  twenty- four  hours  or  12,000,000  gallons  total 
for  the  two  pumps,  at  a  point  two  hundred  and  fifty-five  feet  higher  than  the  crest 
of  the  original  dam,  through  a  24-inch  delivery  main,  and  which  pumps  shall  be  con- 
nected to  the  water  suction  and  delivery  mains  at  the  present  City  pumping  station, 
the  City  to  supply  suction  and  delivery  mains  for  said  pumps,  and  to  operate  and 
maintain  said  pumps;  a  transmission  line  from  the  power  house  at  the  dam  to  the 
City's  steam  power  plant,  and  a  reservoir  of  ten  million  gallons  capacity,  to  be  lo- 
cated at  such  point  as  the  City  may  direct. 

Section  7.  Provides  that  Johnson  shall  begin  actual  work  upon  said  dam  within 
sixty  days  after  the  final  passage  of  the  ordinance,  and  shall  have  expended  on  con- 
struction, within  7  months  from  said  date,  the  sum  of  $25,000  and  shall  have  fully 
equipped  and  completed  the  dam  and  other  work  provided  for,  and  shall  have  said 
dam  and  equipment  ready  for  operation  within  two  years  from  the  date  of  the  final 
passage  of  said  ordinance;  provided,  that  should  any  of  said  work  be  delayed  by 
labor  strikes,  excessive  floods  or  other  causes  not  under  the  control  of  Johnson,  an 
extension  of  time  equal  to  the  time  lost  by  reason  of  any  of  the  above  causes  shall 
be  allowed. 

Section  8.  Provides  that  Johnson  shall  deposit  with  the  City  of  Austin  the  sum 
of  $25,000,  and  deliver  a  full  set  of  plans  and  specifications,  which  are  to  be  held  by  the 
Mayor  upon  the  following  conditions: 

Johnson  agrees  to  expend  within  90  days  after  the  date  of  the  final  passage  of 
the  ordinance,  and  within  the  next  four  succeeding  60-day  periods,  not  less  than  $5,000 
in  each  of  said  periods  for  material  and  work.  If  said  amounts  are  not  expended 
within  the  time  specified,  Johnson  shall  pay  as  liquidated  damages  to  the  City  of  Austin 
the  sum  of  $5,000  for  each  period  in  which  default  has  been  made.  If,  however,  John- 
son commences  said  work  within  60  days,  and  complies  with  all  the  requirements,  and 
expends  $25,000  in  actual  work  and  material  according  to  said  plans  and  specifica- 
tions, within  the  7  months  next  succeeding  the  passage  of  the  ordinance,  then  the 
sum  of  $25,000  shall  revert  to  and  be  paid  by  the  City  of  Austin  to  Johnson. 

Section  9.  Provides  that  Johnson  shall  prosecute  work  so  that  for  each  60-day 
period,  with  the  addition  of  such  time  as  is  herein  provided  for  after  the  aforesaid 
7  months,  there  shall  be  expended  not  less  than  $6,000  in  labor  and  material  under  the 
terms  of  this  ordinance  until  the  completion  of  the  concrete  work  on  the  dam. 


Franchise  Ordinance.  59 

Section  10.  Provides  that  if  defects  develop  in  the  dam,  reservoir  or  other  ap- 
purtenances, or  in  the  power  house  flumes  or  tail  race,  that  if  leaks,  seepage  or  other 
waste  of  water  through,  under  or  immediately  around  the  end  of  the  dam,  headgate 
masonry  or  core  wall  occur,  materially  affecting  the  use  of  the  water  above  the  dam 
for  power  purposes,  then  the  payment  of  the  installments  provided  by  the  ordinance 
shall  be  suspended  until  repairs  are  made.  That  repairs  shall  be  commenced  at  once 
and  prosecuted  diligently  and  be  completed  within  a  reasonable  time,  and  shall  under 
any  circumstances  be  completed  within  18  months  from  the  date  of  written  notice 
from  the  City  of  Austin  demanding  such  repairs.  That  in  the  event  of  repairs  not 
having  been  made  within  18  months,  the  City  at  its  option  may  discontinue  payment 
of  further  installments  or  power  rentals,  and  may  terminate  all  privileges  and  fran- 
chises, and  may  take  immediate  possession  of  all  work  and  material  on  the  premises. 

Section  11.  Provides  that  Johnson  shall  furnish  the  City  all  the  water  power  of 
said  dam  and  shall  guarantee  that  two  of  the  three  generating  units  will  continuously 
generate  at  least  3,300  HP  of  electrical  energy;  and  Johnson  further  warrants  that 
said  machinery  shall  be  sufficient  to  generate  600,000  HPH  of  electrical  energy  within 
any  30  consecutive  days  during  the  life  of  this  contract.  While  the  water  is  flowing 
over  the  crest  of  the  dam,  or  has  a  level  of  one  foot  below  the  crest,  the  power  will 
exceed  the  minimum  named  and  need  not  be  measured.  When  the  water  of  the  lake 
is  reduced  to  a  level  one  foot  below  the  crest  of  the  dam,  which  is  called  the  deficiency 
period,  the  City  shall  measure  the  power  used  by  it,  and  shall  continue  to  measure 
same  during  the  period  when  the  water  shall  be  below  such  level.  The  City  may,  dur- 
ing such  period,  use  the  water  in  the  development  of  power  at  such  times  and  in  such 
quantities  as  it  may  choose,  but  shall  not,  without  the  consent  of  Johnson,  reduce  the 
level  of  the  lake  more  than  18  feet  below  the  crest  of  the  dam.  If  during  such  period 
of  less  than  30  days,  it  should  not  be  possible  with  the  water  power  of  the  dam  and 
with  the  machinery  and  equipment  installed,  to  develop  electrical  energy  at  the  rate 
of  600,000  HPH  for  each  30  days  so  measured  without  lowering  the  lake  more  than 
18  feet  below  the  crest  of  the  dam,  then  for  the  difference  between  the  amount  which 
said  Johnson  binds  himself  to  furnish  at  said  rate  of  600,000  HPH  per  30-day  period, 
and  the  amount  actually  furnished,  the  City  shall  make  a  charge  of  $.0135  per  horse 
power  hour  against  Johnson  and  assigns,  and  such  amount  shall  be  deducted  from  the 
next  installment  due  from  the  City. 

Section  12.  Provides  that  all  power  due  the  City  shall  be  measured  at  the  point 
where  it  is  used,  i.  e.  at  the  present  power  plant  of  the  City  or  at  any  sub-station  of 
said  plant  or  at  any  pump  installed  at  the  dam. 

Section  13.  Provides  that  the  City  shall  control,  operate  and  maintain  all  tur- 
bines, generators,  machinery  and  apparatus  in  the  power  house  at  the  dam,  and  the 
transmission  line  from  the  dam  to  the  City's  present  steam  power  plant,  and  the  elec- 
tric pumps  to  be  installed  in  present  City  pumping  station ;  and  the  City  shall  have 
the  right  to  change,  substitute  or  add  to  said  turbines,  generators,  machinery  and  ap- 
paratus, and  that  Johnson  shall  maintain  and  keep  in  repair  the  dam  and  its  appur- 


60  Report  on  the  Dam  at  Austin,  Texas. 

tenances,  core  wall,  head  gate  masonry,  head  gates,  flumes,  draft  tubes,  reservoir  and 
its  appurtenances,  power  house,  and  the  structural  work  of  the  tail  race. 

Section  14.  Provides  that  the  City  of  Austin  will  pay  Johnson  or  assigns  one 
installment  of  $100,000  and  50  installments  of  $32,400  each;  the  first  installment  to 
be  $100,000  due  and  payable  upon  full  completion  of  the  work,  the  starting  of  the  plant 
and  acceptance  of  same  by  the  City;  the  next  50  installments  of  $32,400  each  to  be 
paid  semi-annually,  the  first  $32,400  installment  to  be  due  and  payable  6  months  after 
the  completion  and  acceptance  of  said  work,  and  the  remaining  installments  to  be  due 
and  payable  one  each  6  months  thereafter  until  all  are  paid.  Said  installments  to 
be  paid  from  the  gross  earnings  of  the  water,  light  and  power  plant  of  the  City,  and 
in  no  event  are  any  taxes  to  be  levied  on  the  taxable  property  within  the  City  for  the 
purpose  of  paying  any  sum  of  money  which  may  become  due  to  Johnson  and  his 
assigns. 

Section  15.  Provides  that  the  City  of  Austin  will,  during  the  construction  work, 
furnish  Johnson  the  use  of  electrical  energy  up  to  50  HP,  or  water  of  equivalent 
value.  Any  electrical  energy  or  water  of  equivalent  value  in  excess  of  said  50  HP, 
to  be  paid  for  at  the  current  rates  charged  the  City's  regular  consumers. 

Section  16.  Provides  that  the  City  of  Austin  shall  have  the  use  of  the  water 
power  developed  by  the  dam  and  power  equipment  and  shall  at  all  times  own  and 
control  the  lake  formed  by  the  dam. 

Section  17.  Provides  that  Johnson  shall  lay  across  the  dam  a  24-inch  main  as 
provided  for  in  said  plans  if  the  City  shall  direct  the  construction  of  the  reservoir 
on  the  west  side  of  the  Colorado  Eiver. 

Section  18.  Provides  that  at  the  expiration  of  the  term  of  the  franchise,  the 
dam,  its  equipment  and  all  the  property  embraced  and  comprehended  in  the  ordi- 
nance, shall  become  the  absolute  property  of  the  City. 

Section  19.  Provides  that  the  City  may  have  access  to  the  books  and  accounts 
of  Johnson  during  the  period  of  construction  and  that  the  City  may  appoint  an  en- 
gineer or  inspector  to  see  that  all  work  done  and  material  used  are  in  strict  accord- 
ance with  the  plans  and  specifications. 

Section  20.  Provides  that  all  notices  to  be  given  by  the  City  to  Johnson  and 
assigns  shall  be  sufficiently  given  by  a  simple  statement  in  writing  deposited  in  the 
post  office  of  the  City,  addressed  to  the  bank  or  other  agent ;  and  during  the  term  of 
construction,  the  engineer  employed  by  the  said  Johnson  in  charge  of  said  work,  shall 
be  the  proper  party  to  which  any  such  notice  shall  be  addressed. 

Section  21.  Provides  that  in  case  of  disagreement  between  the  City  and  John- 
son, the  same  shall  be  left  to  arbitration  by  the  selection  of  one  party  by  the  City  and 
one  party  by  Johnson,  the  two  so  selected  to  select  a  third  party,  and  the  judgment 
of  the  majority  of  the  Committee  so  selected  shall  be  considered  as  a  final  deter- 
mination. 


Franchise  Ordinance.  61 

Section  22.  Provides  that  the  City  shall  have  the  license  and  authority  to  use 
all  parts,  contrivances  and  devices  used  on  the  work,  which  may  be  covered  by  letters 
patent  during  the  life  of  this  contract  and  at  all  times  thereafter. 

Section  23.  Provides  that  the  contract  between  the  City  and  Johnson  shall  be 
held  to  have  been  fully  made  and  agreed  upon  by  the  due  enactment  of  this  ordi- 
nance, and  the  terms  of  said  contract  shall  be  evidenced  by  the  plans  and  specifica- 
tions and  duplicate  copies  of  this  ordinance,  duly  approved  by  the  Mayor  and  at- 
tested by  the  City  Secretary,  under  the  corporate  seal  of  the  City  and  the  signature 
of  the  said  Johnson. 

Section  24.    Provides  that  all  ordinances  in  conflict  are  repealed. 


APPROVED 

J.  Bouldin  Rector 
City  Attorney 

PASSED:  Sept.  7,  1911      APPROVED: 
ATTEST :  Sept.  11,  1911 

Jno.  0.  Johnson  A.  P.  Wooldridge 

City  Clerk  Mayor 

William  D.  Johnson  gives  Frank  S.  Taylor  authority  to  sign  contract,  specifications, 

&c.     June  17,  1911 
Contract  with  Wm.  D.  Johnson  dated  Sept.  22,  1911 

Voted  by  people  Aug.  30,  1911. 
Contract  published  in  Austin  Daily  Tribune  Sat.  and  Sun.,  July  29  and  30,  1911 

LETTEB  FILED  WITH  CITY 

Austin,  Texas,  July  29,  1911 
Hon.  A.  P.  Wooldridge,  Mayor  of  Austin,  Texas. 
Dear  Sir: 

I  have  read  over  the  proposed  ordinance  *  *  *  and  I  agree  to  the  terms  and 
obligations  contained  therein.  I  have  today  deposited  with  you  as  Mayor  a  full  set 
of  plans  and  specifications  referring  to  said  proposed  work  and  the  sum  of  $25,000, 
said  plans  and  specifications  and  the  said  sum  of  money  to  be  held  by  you  upon  the 
conditions  contained  in  said  proposed  ordinance. 

Very  truly  yours, 

(Signed)          Wm.  D.  Johnson. 

THE  CONTRACT  SPECIFICATIONS 

The  specifications  accompanying  the  above  ordinance  and  made  a  part  of  the 
contract  are  exceedingly  general  in  character  and  intended  to  be  supplemented  by 
detailed  specifications  to  be  afterwards  furnished.  A  few  of  the  important  features 
of  these  specifications  are  abstracted  as  follows,  italics  are  used  to  call  attention  to 


62  Report  on  the  Dam  at  Austin,  Texas. 

important  passages  and  the  paragraph  numbers  are  used  for  convenience  in  refer- 
ence and  are  not  a  part  of  the  original : 

ABSTRACT  OF  CONTRACT  SPECIFICATIONS 

1.  These  specifications  are  intended  to  include  the  work,  material,  machinery, 
etc.,  necessary  to  the  erection  and  completion  of  a  dam  across  the  Colorado  River  at 
Austin,  Texas,  at  or  near  the  location  of  the  dam  formerly  erected  across  said  river 
by  the  City  of  Austin ;  the  construction  and  equipment  of  a  power  plant  at  said  dam ; 
the  construction  of  a  ten  million  gallon  reservoir;  the  furnishing  and  setting  of  two 
electric  motor  driven  centrifugal  pumps  in  the  City 's  pumping  station ;  the  construc- 
tion of  a  transmission  line  from  said  power  plant  at  the  dam  to  the  City's  steam 
power  plant,  and  all  connections  and  appurtenances  pertaining  to  these  several  items ; 
all  to  be  done  for  the  City  of  Austin,  Texas,  by  Wm.  D.  Johnson  and  his  assigns,  in  a 
thorough  and  workmanlike  manner,  and  in  accordance  with  the  general  specifications 
hereinafter  set  forth. 

2.  It  is  specified  and  understood  that  these  plans  and  specifications  are  meant  to 
embrace  every  essential  element  necessary  to  the  building,  furnishing  and  completing 
of  the  dam,  core  wall,  headgate  masonry,  headgates,  power  house,  flumes,  draft  tubes, 
transmission  line,  two  electric  motor  driven  centrifugal  pumps,  reservoir,  and  all 
work  embraced  in  these  several  items,  and  any  essential  element  not  mentioned  here- 
in shall  be  considered  as  much  a  part  of  these  specifications  as  if  specifically  set 
forth  herein.     It  is  also  understood  that  all  the  work  and  materials  specified  or  im- 
plied herein,  or  intended  to  be  covered  by  these  specifications,  shall  be  performed  or 
furnished  by  Wm.  D.  Johnson  and  his  assigns  (hereinafter   called   the    Contractor) 
unless  otherwise  stated  herein. 

3.  These  specifications  and  the  accompanying  designs  and  drawings  are  subject  to 
any  changes  that  may  in  the  opinion  of  the   Engineer-in-chargef   be   desirable;   pro- 
vided such  changes  do  not  decrease  the  amount  of  equipment  in  the  power  house,  the 
height  or  stability  of  the  dam,  the  size  of  the  reservoir,  or  in  any  way  diminish  the 
capacity  or  completeness  of  the  installation,  or  in  any  way  lower  the  standard  of  the 
grade  of  construction. 

4.  Dam. — Specifies  materials,  tools,  etc. 

5.  Excavation. — All  loose  material  lying  above  the  rock  bed  of  the  stream  shall 
be  removed  from  the  site  of  the  dam  by  sluicing  or  otherwise,  and  sufficient  excava- 
tion for  each  cross  wall  shall  be  made  into  the  rock,  to  secure,  in  the  judgment  of  the 
engineer,  good  foundation  and  prevention  against  slipping  of  the  dam — all  decayed 
or  otherwise  unsuitable  portions  of  rock  being  removed. 

6.  Trenches  for  cut-off  walls,  at  least  two  feet  and  for  core  wall  at  least  three 
feet  in  width,  and  extending  downward  at  least  two  feet  into  the  solid  rock,  shall  be 
made  across  the  stream  on  the  up  stream  and  down  stream  sides  of  the  new  portion 
of  the  dam,  and  along  such  portion  of  the  old  dam  as  borings  shall  indicate  to  be  nec- 
essary and  in  accordance  with  plans. 


Abstract  of  Specifications.  63 

7.  Grouting. — Liquid  grout,  composed  of  a  mixture  of  cement,  fine   sand  and 
water,  in  proportions  determined  by  the  engineer    (but  not   with  more   than  three 
parts  of  sand  to  one  part  of  cement),  shall  be  pumped  into  two-inch  drill  holes  made 
in  the  rock  every  thirty  feet  or  less,  if  necessary,  along  the  upstream  face  of  the  en- 
tire dam,  under  a  pneumatic  pressure  of  not  less  than  fifty  pounds  per  square  inch. 
The  object  of  this  is  to  cause  the  rock  underlying  the  up  stream  face  of  the  dam  below 
bottom  of  cut-off  wall  to  become  saturated  with  the  grout,  if  it  be  porous  or  "seamy" 
or  otherwise  pervious,  in  order  to  prevent  waste  of  water  by  percolation  through 
the  strata  below  the  cut-off  walls  of  the  dam.     In  case  cavities  are  discovered  by  this 
drilling,  or  in  case  any  other  unusual  arrangement  of  the  strata  is  discovered,  the 
arrangement  of  holes  may  be  changed,  and  the  rock  under  the  up  stream  face  of  the 
dam  may  be  filled  and  made  impervious  in  any  other  practical  manner. 

8.  Cut-off  Walls. — In  the  trenches  for  cut-off  walls,  excavated  two  feet  wide  and 
down  to  solid,  impervious  rock  foundation,  which  borings  have  indicated  to  be  at 
least  six  feet  in  thickness,  etc.,  etc.     (This  is  followed  by  a  brief  description  of  the 
width  of  the  walls  and  the  composition  of  the  concrete  of  which  they  are  to  be  con- 
structed and  authorizes  the  filling  of  additional  trench  back  of  the  walls,  with  clay 
puddle.) 

9.  Supporting  Walls. — Describes  the  walls  supporting  the  deck,  and  describes  the 
deck  of  the  dam. 

10.  Old  Portions  of  Dam. — Portions  of  the  original  dam,  as  constructed  in  1890 
and  1893,  will  be  retained  and  used  as  portions  of  the  finished  structure  to  be  com- 
pleted under  these  plans  and  specifications.     This  old  work  shall  be  thoroughly  in- 
spected, and  wherever  there  are  loose  stones  or  imperfect  joints  in  the  masonry,  the 
work  shall  be  made  good  to  the  satisfaction  of  the  engineer.     Pointing  of  the  joints 
shall  be  done  where  necessary. 

11.  Great  care  shall  be  taken  to  thoroughly  bond  the  new  work  to  the  old  struc- 
ture, drill  holes  being  made  into  same  in  order  that  anchor  bars  may  be  continued 
into  the  new  work,  to  thoroughly  tie  the  structure  together.     The  contractor  assumes 
the  responsibility  for  the  perfect  stability  and  effectiveness  of  the  portions  of  the 
old  dam  as  parts  of  the  finished  structure. 

12.  Gates   and  Appurtenances. — Describes  flood  gates  to  raise  water  five  feet 
above  the  crest  of  the  old  dam  and  permit  the  passage  of  floods  of  200,000  cubic  feet 
per  second. 

13.  Sluice  Gates. — Describes  sluice  gates  and  discharge  passages. 

14.  Core  Watt. — Describes  wall  300  feet  long  to  be  built  in  front  and  east  of 
head  works. 

15.  Track — Walk  and  Pipe  Line. — Describes  track  and  walk  on  top  of  gate  piers 
and  24"  cast  iron  water  pipe  to  be  laid  if  City  so  elects. 

16.  Reservoir. — Describes  reinforced  concrete  reservoir  of  10  million  gallons 


64  Report  on  the  Dam  at  Austin,  Texas. 

capacity,  the  excavation  of  which  is  not  to  exceed  an  average  of  4  feet  beyond  which 
extra  compensation  will  be  required. 

17.  Timber. — Describes  timber  used  as  a  permanent  part  of  structures. 

18.  Cement. — Describes  cement  to  be  used. 

19.  Sand. — Describes  sand  for  concrete. 

20.  Stone  or  Gravel. — Describes  stone  or  gravel  for  use  in  concrete. 

21.  Structural  Steel  and  Steel  Reinforcement. — Description. 

22.  Forms  for  Concrete. — Description. 

23.  Proportion  of  Ingredients. — Described. 

24.  Mixing. — Described. 

25.  Placing  of  Concrete. — Described. 

26.  Power  House. — Described. 

27.  Head  Gates  and  Hoists. — Described — also  forebay  and  racks. 

28.  Intakes. — Described. 

29.  Draft  Tubes. — *  *  *  The  material  of  the  intakes  or  draft  tubes  now  forming 
a  part  of  the  old  plant  may  be  used,  if  suitable,  but  in  any  event  the  metal  must  be 
of  reasonably  uniform  thickness  and  strength  throughout.     These  draft  tubes  must 
be  properly  and  adequately  supported  in  a  thoroughly  workmanlike  manner. 

30.  Tail  Race. — It  is  understood  that  the  outlet  for  water  from  the  turbines  used 
in  the  old  power  house,  is  buried  with  earth  at  the  present  time  a  considerable  num- 
ber of  feet  and  that  the  contractor  shall  uncover  these  openings  and  excavate  a  trench 
through  the  earth  embankment  at  an  an  angle  of  approximately  sixty  degrees  to  the 
north  and  south  line  of  the  power  house,  in  a  downstream  direction  from  the  portion 
of  the  old  power  house  now  standing,  to  the  river  at  low  water.     In  this  trench  is  to 
be  placed  a  tunnel,  or  channel,  of  reinforced  concrete,  of  ample  capacity  to  remove 
the  tail  water  from  the  turbines,  which  will  be  installed  by  the  contractor  at  the  pres- 
ent time,  and  also  from  the  1000  HP  additional  turbines  for  which  the  contractor  is 
to  provide  intake,  when  all  of  said  turbines  are  operating  at  full  gate. 

31.  If  channel  be  used,  the  wall  on  the  upstream  side  of  the  channel  wall  shall 
be  so  buttressed  as  to  withstand  any  outside  pressure  that  is  likely  to  be  brought  to 
bear  upon  it,  and  it  shall  be  of  such  a  height  that  any  flood  water  cannot  wash  earth 
or  silt  into  the  channel  over  the  top  of  said  wall,  either  at  the  time  said  channel  is 
constructed,  or  at  any  subsequent  time. 

32.  This  tail  race  tunnel,  or  channel,  shall  rest  upon  a  good  foundation,  and  shall 
be  anchored  to  rock  at  intervals  of  not  more  than  twenty-five  feet,  and  shall  be  of  suf- 
ficient strength  to  withstand  any  pressure  from  within  or  without  to  which  it  is  likely 
to  be  subjected. 

33.  Power  House  Equipment. — Described. 

34.  Pumps. — Described. 

35.  Transmission  Line. — Described. 

36.  Engineer. — Wherever  the  word  "Engineer"  is  used  in  these  specifications, 
the  engineer  representing  Win.  D.  Johnson,  and  his  assigns,  is  meant.     The  City  of 
Austin  shall  have  the  right,  however,  to  appoint  a  supervising  engineer  on  the  work, 


Abstract  of  Specifications.  65 

whose  duty  it  shall  be  to  see  that  the  specifications  and  plans  are  observed  and  fol- 
lowed in  every  material  particular;  and  whenever  in  the  judgment  of  the  City's  said 
representative  engineer,  the  contractor  is  doing  work  or  furnishing  material  which 
is  not  in  accordance  with  plans  or  specifications,  or  which  is  otherwise  improper,  it 
shall  be  his  duty  to  call  the  attention  of  the  contractor's  engineer  to  the  discrepancy, 
and  if  the  two  engineers  should  fail  to  agree,  then  the  City's  engineer  shall  report  to 
the  proper  City  official  the  difference  of  opinion,  and  the  circumstances  in  full.  Said 
City  official,  on  receipt  of  the  information  as  set  forth,  may  then  immediately  proceed 
as  provided  under  the  Arbitration  Clause,  Section  21  of  the  ordinance  concerning  the 
rebuilding  of  the  dam,  dated  September  11,  1911. 

37.  It  is  expressly  understood  that  the  above  specifications  and  the  plans  accom- 
panying same,  are  intended  to  cover,  in  a  general  way  only,  the  work,  materials  of 
construction  and  the  equipment  referred  to,  and  it  is  hereby  further  required  that  the 
contractor  shall  furnish,  in  duplicate,  detailed  plans  and  specifications  of  all  materials 
to  be  furnished,  work  to  be  done,  and  equipment  to  be  installed,  to  the  City  of  Austin, 
Texas,  at  as  early  a  date  as  possible  after  the  signing  of  the  contract ;  and  in  any 
event  such  detailed  plans  and  specifications  shall  be  furnished  the  City,  concerning 
any  and  all  work  to  be  done  or  equipment  to  be  installed,  or  material  to  be  furnished, 
before  said  work  begins,  or  equipment  is  placed,  or  material  is  furnished. 

38.  The  City's  engineer  shall  have  access  at  all  times  to  all  plans  and  specifica- 
tions which  the  contractor  may  desire  to  use,  and  the  opportunity  to  consider  same 
before  the  work  represented  thereby  begins. 

PLANS 

The  plans  which,  together  with  the  ordinance  and  specifications,  constituted  the 
contract  between  Wm.  D.  Johnson  and  the  City  of  Austin,  consisted  of  seven  sheets  as 
follows : 

1.  General  Plan  and  Elevation  of  Proposed  Dam,  Power  House  and  Connec- 
tions. 

2.  Section  of  proposed  reinforced  Concrete  Dam  with  Elevation  and  Plan 
showing  Proposed  Arrangement  of  Walls,  Piers,  etc.     Piers  18"  thick  12'  c  to  c 
Upstream  deck  (by  scale)  21"  thick  at  base,  12"  thick  at  top  of  dam;  downstream 
deck  by  scale  12"  thick.     Width  of  dam,  125'  9". 

3.  Section  showing  Old  and  New  Portions  of  Dam.     Gate  Pier  on  Old  Dam 
10'  c  to  c. 

4.  Section  showing  Sluice  Gates  on  Reinforced  section  of  Dam,  each  Sluice 
Gate  8'  deep  3y2'  wide.    Hydraulic  Cylinders  for  operating  Gates  inside  of  Dam. 

5.  Plan  showing  Location  of  Sluice  in  Proposed  Dam.     Four  double  gates. 

6.  Plans  of  Automatic  Crest  Gates,  Bearings  and  Pivot  Castings. 

7.  Isometric  Drawing  of  Crest  Gates. 

The  type  of  reinforced  concrete  dam  which  was  shown  in  these  plans  was  appar- 
ently based  on  Patent  1,010,612,  granted  to  C.  F.  Doebler,  Dec.  5,  1911. 


APPENDIX  3 

WORK  UNDER  JOHNSON  CONTRACT  or  1911 — INCLUDING  CHANGES  IN  PLANS  PROGRESS  OF 
WORK  AND  DEVELOPMENT  OF  CONDITIONS 

The  work  under  the  Johnson  franchise  contract  of  1911  was  started  on  Septem- 
ber 22,  1911,  and  prosecuted  by  force  account  until  June,  1912,  when  a  contract  was 
entered  into  with  the  William  P.  Carmichael  Company  of  St.  Louis. 

First  Change  in  Plans. — A  new  general  plan,  numbered  "Gen.  8",  apparently 
based  on  Patent  1,010,131,  granted  to  W.  S.  Edge,  Nov.  28, 1911,  was  substituted  and 
approved  by  A.  C.  Scott,  Consulting  Engineer  for  the  City,  on  March  15,  1912.  This 
change  was  approved  with  the  knowledge  and  consent  of  the  City  Council.  This 
new  plan  shows  a  rearrangement  of  the  interior  walls  of  the  dam  which  were  oblique 
to  the  axis  of  the  dam  in  the  original  plans,  normal  to  the  axis  in  the  new  plan. 
The  spacing  of  the  gate  piers  was  also  changed  from  12  foot  centers  on  the  new  por- 
tion of  the  dam  and  10  foot  centers  on  the  old  portion  of  the  dam,  to  20  foot  centers 
on  the  entire  dam. 

Mr.  Wm.  D.  Johnson  assigned  his  rights  and  franchise  (in  April,  1912)  to  The 
City  Water  Power  Company  (a  Connecticut  corporation)  organized  to  carry  out  the 
proposed  work.  Mr.  Lamar  Lyndon  was  employed  as  Consulting 'Engineer  and  Mr. 
Frank  S.  Taylor  as  Resident  Engineer,  and  the  work  was  carried  out  under  their 
direction.  Dr.  A.  C.  Scott  of  Dallas,  was  appointed  Consulting  Engineer  for  the 
City,  and  about  October  of  1912,  Mr.  S.  S.  Posey  was  appointed  Inspector  for  the 
City. 

Approval  of  Detailed  Plans  Including  Certain  Changes. — In  May,  1912,  a  set  of 
nine  detailed  plans  (numbered  C-9  to  C-17  inclusive)  were  submitted  by  Mr.  Taylor 
to  Dr.  Scott,  and  after  examination  were  approved  by  him  in  a  letter  dated  May  20, 
1912,  to  the  Wm.  P.  Carmichael  Construction  Company.  The  original  plans  filed 
with  the  ordinance  and  specifications,  as  before  noted,  were  very  general  in  character 
and  the  adequacy  of  the  structure  outlined  therein  could  hardly  have  been  deter- 
mined from  the  data  given  therein  without  additional  assumptions. 

Apparently  no  attempt  was  made  on  the  part  of  the  City  to  determine  the  safety 
or  adequacy  of  the  structure  proposed,  but  full  reliance  was  placed  on  the  guarantee 
(see  Sees.  10  and  13  of  franchise  ordinance). 

The  detailed  plans,  C-9  to  C-17  inclusive,  were  in  sufficient  detail  to  permit  of 
analysis.  The  new  plans  were  not  compared  by  Dr.  Scott  with  the  original  plans  for 
the  reason  above  stated.  (See  letter  from  Dr.  Scott  to  E.  C.  Bartholomew,  dated 
April  6,  1916,  on  file  with  City)  and  Dr.  Scott  did  not  notify  the  City  of  the  changes 
in  the  detailed  plans  from  the  original  plans. 


Progress  and  Character  of  Work.  67 

These  plans  were  furnished  in  accordance  with  paragraph  37  of  the  foregoing 
abstract  of  specifications.  Under  paragraph  38  of  the  abstract  (page  25  of  the  orig- 
inal), the  Company  was  obligated  to  furnish  such  plans  for  the  consideration  of  the 
City's  Engineer  before  beginning  work,  but  no  provision  of  the  contract  required  the 
approval  of  the  City  Council,  although  if  changes  were  involved  outside  of  the  limits 
prescribed  in  paragraph  3  of  this  abstract  (page  2,  original),  they  could  not  be  legally 
made  without  such  approval. 

The  principal  change  made  in  those  detailed  plans  was  a  reduction  in  the  width  of 
the  dam  from  125'  9"  (shown  on  Drawing  2  of  the  original)  to  93  feet  (shown  on 
Drawing  C-17  of  the  new  plans),  and  a  rearrangement  of  the  dam  crest  made  neces- 
sary by  the  reduction  in  width.  (See  Fig.  5,  page  17.) 

The  City  Council,  not  having  its  attention  called  to  this  change,  remained  un- 
aware of  the  same,  and  the  Contractor  on  the  basis  of  the  approval  of  the  plans  by  the 
City's  Engineer,  proceeded  with  the  construction  in  accordance  with  those  plans. 

Progress  and  Character  of  Work. — Work  was  apparently  begun  at  an  early  date 
on  the  power  house.  The  remains  of  the  original  power  station  were  extended  north 
about  30  feet  (see  Fig.  29,  page  69)  and  the  plan  of  the  equipment  was  changed 
from  the  original  plan  (see  Fig.  14,  page  43)  to  that  shown  by  Fig.  28,  page  68.  The 
turbines,  electrical  machinery  and  centrifugal  pumps  for  the  City  water  works  were 
received  and  set  in  the  spring  of  1913.  The  test  of  the  pumps  showed  that  they  had 
only  about  two-thirds  of  the  guaranteed  capacity.  After  various  tests,  it  was  finally 
agreed  (in  1915)  that  the  Company  should  install  an  extra  pump,  thus  giving  the  City 
three  pumps,  each  of  a  capacity  of  four  million  gallons  per  day  instead  of  the  con- 
tract requirements  (see  Sec.  6  of  the  ordinance)  of  two  pumps  each  of  a  capacity  of 
six  million  gallons  per  day. 

The  reservoir  specified  in  the  contract  was  completed  in  July,  1913,  and,  it  is  be- 
lieved, has  been  in  continuous  use  to  the  present  time. 

The  work  on  the  foundation  of  the  dam  was  constructed  at  times  when  the  con- 
ditions of  the  flow  of  the  river  would  permit. 

Much  difficulty  and  delay  were  occasioned  by  frequent  floods  in  the  Colorado 
River,  and  the  cofferdams  built  for  construction  purposes  were  washed  out  some 
twelve  or  thirteen  times  while  the  work  was  in  progress.  In  general,  the  work  seems 
to  have  been  well  and  properly  done  so  far  as  the  plans  and  specifications  provided. 
In  minor  instances,  objections  were  made  by  the  Inspector,  Mr.  Posey,  principally 
as  to  the  depth  to  which  the  cut-off  and  core  trenches  were  carried  and  as  to  the  mix- 
ture used  in  the  foundation  concrete.  These  matters  were  adjusted  from  time  to 
time  by  the  Consulting  Engineer,  Dr.  Scott. 

The  concrete  work  seems  sound  and  impermeable  though  somewhat  rough.  This 
roughness  is  of  no  serious  importance  except  in  the  gate  piers  where  the  roughness  of 
the  work  together  with  the  swelling  of  the  forms  has  apparently  made  it  difficult  to  fit 
the  crest  gates  so  as  to  permit  of  the  automatic  action,  for  which  they  were  designed, 
and  at  the  same  time  to  prevent  serious  leakage. 


68 


Report  on  the  Dam  at  Austin,  Texas. 


A  general  plan  and  elevation  of  the  work  as  constructed  are  shown  in  Fig.  4, 
page  15.  The  foundation  work  was  described  in  an  article  written  by  Mr.  Frank  S. 
Taylor  for  the  Engineering  Record  of  May  29,  1915,  as  follows : 

"The  cutoff  wall  was  carried  down,  in  many  instances,  a  considerable  depth 
below  the  footings  of  the  buttresses.  This  wall,  on  the  upstream  side  of  the  dam, 
was  poured  in  a  trench  which  had  previously  been  tested  by  numerous  drill 


FIGUBE  28 — Reconstructed  Power  House  and  Arrangement  of  Machinery  as   Installed 
under  the  Johnson  Contract.     (Bng.  Rec.  June  10,  1915.) 

holes,  put  down  in  the  bottom  of  the  trench.  Where  defects  were  found,  they 
were  remedied  by  grouting.  The  test  holes  were  first  spaced  12  feet  apart  in  the 
bottom  of  the  trench.  Compressed  air  was  turned  into  them,  one  by  one,  to  dis- 
cover underground  connections  between  adjacent  holes.  Wherever  the  com- 
pressed air  would  blow  out  of  one  or  more  of  the  other  holes,  it  was  considered 
that  the  entire  seams  or  crevices  between  the  two  holes  were  reached  by  the  drill 
holes  then  made.  Grout  would  then  be  forced  into  one  of  the  holes  until  it  began 
to  blow  out  of  the  others.  It  was  then  considered  that  the  rock  lying  below  the 
cutoff  wall  trench  and  between  the  holes  had  been  made  tight.  Wherever  no 
connection  could  be  established  between  the  holes  12  feet  apart,  intermediate 
holes  were  drilled,  thus  making  the  drill  holes  only  6  feet  apart  along  certain 


Progress  and  Character  of  Work.  69[ 


111      T     1 


FIGURE  29 — Power  House  during  Reconstruction,Showing  Addition  to  Remains  of  Old  Station. 


FIGURE  30 — Rock  Trenches  for  Foundation  Wall  of  New  Dam. 


io'A  Report  on  the  Dam  at  Austin,  Texas. 


FIGURE  31— Rock  Trenches  for  Foundation  Wall  of  New  Dam. 


FIGURE  32— Concrete  Foundation  of  Cross  Walls       FIGURE  33— Concrete  Mat  in  Front  of  Sluiceways 
and  Excavation  for  Concrete  Mats  for  Sluice- 
ways.    (Note  Narrow  Trenches.) 


Progress  and  Character  of  Work.  71 

portions  of  the  cutoff-wall  trench.  If,  after  this  was  done,  no  connection  would 
be  established  between  adjacent  holes,  additional  holes  intermediate  to  those  6 
feet  apart  were  drilled,  bringing  the  distance  to  3  feet. 

"In  nearly  every  instance  where  these  holes  were  made  water  flowed  freely 
through  them,  sometimes  spouting  up  3  or  4  feet,  thus  proving  conclusively  con- 
nection between  the  holes  made  inside  the  cofferdam  and  the  surrounding  body  of 
water.  As  grout  would  be  forced  into  the  holes,  the  velocity  of  water  flowing  out 
of  them  would  gradually  diminish,  until  it  would  entirely  stop.  In  many  cases, 
where  grout  was  forced  into  a  hole,  the  flow  of  water  through  other  holes,  some- 
times as  far  distant  as  GO  feet,  would  be  stopped  and  the  grout  would  finally  show, 
rising  out  of  adjacent  holes,  proving  that  the  underground  seams  between  these 
two  holes  had  been  thoroughly  filled  with  grout.  In  placing  the  grout  the  pres- 
sure on  the  liquid  mixture  was  gradually  increased  from  a  few  pounds  to  a  max- 
imum of  80  pounds. ' ' 

As  stated  by  Mr.  Taylor,  the  cutoff  walls  and  all  of  the  foundation  walls  of  the 
new  dam  seem  to  have  been  constructed  in  narrow  trenches  through  rock  which  was 
found  unfit  for  foundation  purposes.  (See  Figs.  29,  30,  31,  32  and  33,  pages  69  and  70.) 
In  consequence  of  this  method,  it  is  quite  apparent  that  the  Engineers  or  Contractors 
on  the  work  never  had  a  comprehensive  view  of  the  foundation  rock  as  a  whole  but 
examined  it  only  along  the  narrow  lines'  of  these  excavations. 

The  foundation  work  as  above  described  temporarily  fulfilled  its  purposes,  and 
the  Engineers  of  the  City,  Messrs.  Scott  and  Posey,  in  their  report  to  Superintendent 
E.  C.  Bartholomew,  stated : 

"The  Sluice  gates  were  closed  on  December  12,  1914,  and  on  the  same  date, 
work  on  the  last  cofferdam  (below  the  dam)  was  started  and  rushed  forward  day 
and  night  to  completion.  This  cofferdam,  when  completed,  inclosed  some  ten 
or  twelve  acres  of  the  river  bed,  and  after  being  pumped  out  for  service,  an  in- 
spection of  the  foundation  walls  and  general  condition  of  the  partially  completed 
structure  was  readily  made.  Such  inspection  disclosed  a  significant  fact,  viz: 
that  while  the  head  of  water  on  the  structure  at  the  time  was  about  fifty  feet, 
the  leakage  through  the  same  was  entirely  insignificant  in  quantity;  which 
showed  that  the  cut-off  wall,  foundation  structure  and  upstream  deck  had  been 
made  impervious  as  required.  Further  evidence  that  satisfactory  construction 
work  had  been  done,  was  shown  by  the  fact  that  only  one  eight-inch  pump  was  re- 
quired to  keep  the  water  out  of  the  large  area  inclosed  by  the  cofferdam,  while 
the  downstream  deck  construction  was  in  progress;  and  practically  all  of  the 
water  which  was  thus  pumped  came  in  from  the  downstream  side  of  the  basin 
through  the  sand  bank  constituting  that  portion  of  the  cofferdam." 

On  May  20,  1914,  part  of  the  retaining  wall  along  the  river  between  the  power 
house  and  the  dam,  which  had  been  constructed  under  the  franchise,  fell  out  into  the 
river  and  was  reconstructed,  apparently  on  original  plans. 


72  Report  on  the  Dam  at  Austin,  Texas. 

On  February  16,  1915,  the  water  above  the  dam  first  reached  the  60-foot  level 
(the  height  of  the  original  dam)  since  the  failure  of  the  original  dam  in  1900. 

The  roof  of  the  conduits  leading  through  the  dam  from  the  sluice  gates  were 
destroyed  by  the  pressure  of  the  discharging  water,  apparently  some  time  early  in 
1915. 

In  March  1915  the  turbines  were  tested  and  are  reported  to  have  given  results 
better  than  the  guarantees,  although  I  have  not  been  able  to  secure  copies  of  the 
test. 

Early  in  April,  1915,  the  work  being  regarded  as  nearly  complete,  the  City  ad- 
vanced the  Carmichael  Company  the  sum  of  $21,000,  which  had  been  assigned  to  the 
Contractor  by  the  City  Water  Power  Company  from  the  first  payment  due  on  accep- 
tance of  the  work.  This  was  done  by  the  City  in  order  to  secure  the  prompt  comple- 
tion of  the  work. 

In  the  flood  of  April,  1915,  four  of  the  large  crest  gates  went  out  but  were  re- 
placed immediately  thereafter.  A  considerable  amount  of  drift  was  caught  and  held 
by  the  gates  and  piers.  The  gates  were  found  to  leak  badly,  and  a  device  for  stanch- 
ing was  applied  which  prevented  their  free  action  and  later  is  believed  to  have  been 
one  of  the  causes  of  their  destruction  when  the  gates  were  suddenly  opened  by  the 
excessive  rise  in  the  river. 

Previous  to  the  destruction  of  the  old  dam  in  1900,  much  rock  was  torn  out  by 
the  floods  from  the  river  bed  immediately  in  front  of  the  dam  and  thrown  up  in  a 
pile,  the  face  of  which  averaged  about  90  feet  from  the  toe  of  the  dam.  (See  Pig.  23, 
page  52.)  When  the  old  dam  was  destroyed,  this  pile  of  rock  was  augmented  by  rock 
from  the  old  dam,  although  much  of  the  rock  previously  deposited  and  much  of  the 
material  from  the  old  dam  were  carried  farther  down  the  stream.  In  the  construc- 
tion of  the  new  tailrace,  a  somewhat  shallow  channel  was  cut  through  the  bar  below 
the  rock  pile,  but  no  wall  was  constructed  as  provided  in  the  contract  to  protect  the 
raceway  from  filling.  (Sec.  31,  Abstract  of  Specifications,  page  64.)  In  the  flood  of 
April,  1915,  this  raceway  was  partially  filled  by  debris  from  this  pile  of  rocks. 

On  April  20,  1915,  the  brick  retaining  wall  between  the  power  house  and  dam 
again  fell  out  carrying  with  it  a  portion  of  the  wall  of  the  power  house.  About  this 
time  a  leak  appeared  below  the  cutoff  wall  in  panel  number  six. 

These  various  mishaps  apparently  created  a  suspicion  on  the  part  of  the  City 
officials  that  the  work  as  constructed  under  the  plans  was  not  entirely  in  accordance 
with  the  spirit  of  the  contract,  and  the  City  refused  to  accept  the  work  until  it  was 
entirely  completed  in  an  acceptable  manner. 

The  City  Water  Company  had  originally  issued  $750,000  in  bonds,  but  had  taken 
down  and  sold  bonds  of  a  par  value  of  $412,500  on  which  they  realized  75  per  cent, 
or  $309,375,  of  which  amount  apparently  $261,640.07  was  paid  to  the  Contractors,  and 
the  balance  went  to  pay  various  other  expenses.  The  Contractors,  W.  P.  Carmichael 
&  Company,  had  already  expended  a  considerable  amount  in  excess  of  their  guaran- 
teed maximum  contract  price  and  were  apparently  unable  or  unwilling  to  furnish 


Progress  and  Character  of  Work.  73 

additional  funds  for  this  work  until  they  were  assured  of  its  final  acceptance.  It  was 
to  complete  the  work  that  the  City  advanced  the  sum  of  $21,000  before  mentioned. 
Under  these  conditions  a  committee  of  the  bond  holders  had  been  organized,  and, 
with  the  hope  of  completing  the  work  so  th  at  it  would  be  accepted  and  additional 
bonds  could  be  taken  down  and  sold  to  meet  the  indebtedness  of  the  City  Water 
Works  Company,  advanced  the  Contractors  the  sum  of  $11,242.62. 

About  this  time  (May,  1915),  the  J.  G.  White  Engineering  Company  of  New  York 
was  appointed  engineer  for  the  work.  The  retaining  wall  which  had  twice  failed, 
was  rebuilt  on  apparently  substantial  lines,  and  various  other  work  toward  complet- 
ing the  plant  was  carried  out.  The  extra  pump  before  mentioned  was  purchased  and 
installed.  The  replacement  of  the  roof  of  the  discharge  conduits,  which  had  failed, 
was  started,  but  the  available  funds  were  exhausted  before  this  work  could  be  com- 
pleted. 

In  September,  1915,  a  still  greater  flood  occurred  in  the  Colorado  River.  Twenty 
of  the  large  crest  gates  went  out  (see  Fig.  8,  page  25)  together  with  most  of  the 
small  ones.  The  tailrace  was  again  partially  filled  (see  Fig.  9,  page  25),  and  the 
turbine  draft  tubes  blocked  (see  Figs.  8  and  9,  page  25),  and  the  work  on  the  pro- 
ject practically  ceased. 

About  this  time  the  City  Officials  became  aware  that  the  dam  had  been  reduced 
in  width.  The  various  difficulties  with  the  crest  gates  convinced  them  that  a  ma- 
terial change  in  the  design  of  the  crest  of  the  dam  would  be  essential.  The  leak  under 
the  dam  was  also  an  unknown  factor  which  involved  much  uncertainty. 

In  order  to  determine  the  changes  that  had  been  made  from  the  original  plans, 
Mr.  S.  S.  Posey,  Inspecting  Engineer,  who  had  been  on  the  work  practically  from  the 
beginning,  was  requested  to  submit  a  report  on  the  subject.  His  report  is  as  fol- 
lows: 

Austin,  Texas,  May  20,  1916. 
Mr.  E.  C.  Bartholomew, 

Supt.  Water  and  Light  Dept. 
Dear  Sir: 

.  At  your  request,  I  have  gone  over  the  plans  and  specifications  for  the  re- 
building of  the  Austin  Dam  and  made  a  list  of  the  changes  which  the  engineers 
have  made  in  building  the  structure.  I  may  have  omitted  a  few  minor  changes 
but  the  more  important  ones,  whether  favorable  or  unfavorable,  have  been  noted. 
Trusting  that  the  attached  list  will  meet  your  requirements,  I  am 

Yours  very  truly, 

(Signed)  S.  S.  Posey, 

Inspecting  Engineer. 


74  Report  on  the  Dam  at  Austin,  Texas. 

CHANGES  MADE  IN  REBUILDING  THE  AUSTIN  DAM 

1.  The  Eansome  type  was  proposed,  the  Edge  type  was  used.     This  change 
was  taken  up  with  the  City  Council  and  considered  principally  in  a  re-arrange- 
ment of  the  supporting  walls.     On  the  original  drawings  some  of  the  walls  were 
not  at  right  angles  to  the  decks  or  to  the  axis  of  the  dam.     As  built,  they  are  at 
right  angles  to  both  and  are  spaced  20  ft.  apart  instead  of  24  ft. 

2.  The  base  of  the  dam  was  narrowed  up  from  125'  9"  to  93'  0",  modifying 
the  crest  so  that  it  overhangs  the  upstream  deck.     This  did  away  with  one  of  the 
longitudinal  walls  bracing  the  upstream  deck. 

3.  Large  crest  gates  increased  in  length  from  about  ten  to  eighteen  feet. 

4.  Small  crest  gates  increased  in  length  from  about  eight  to  eighteen  feet. 

5.  Foot  bridge  on  top  of  dam  changed  from  steel  I-beam  and  wood  construc- 
tion to  reinforced  concrete  and  wood,  to  make  it  strong  enough  to  support  the 
derrick  car  which  they  expected  to  use  for  handling  the  crest  gates  and  drift. 

6.  The  specifications  call  for  a  reinforced  concrete  floor  supported  by  I- 
beams  in  the  Power  House;  built  partly  on  earth  fill  and  reinforced  concrete 
slab  supported  by  reinforced  concrete  girders. 

7.  Large  crest  gates  made  in  two  weakly  connected  halves  instead  of  one 
well-braced  whole,  as  shown  on  sheet  No.  6  of  the  original  drawings. 

8.  Middle  bascule  and  intermediate  pier  introduced  in  center  of  openings 
for  large  crest  gates,  adding  an  additional  obstruction  to  drift. 

9.  Bascule  castings  changed  from  rack  type  to  plain. 

10.  Location  of  sluiceways  changed  from  the  original  plan,  three  being  lo- 
cated in  the  river  channel  instead  of  one. 

11.  Thickness  of  supporting  walls  changed  from  one  foot  at  base  to  two  feet 
six  inches  at  the  same  point,  diminishing  to  one  foot  at  the  top,  thus  increasing 
the  bearing  on  the  foundation. 

12.  Thickness  of  upstream  deck  slab  increased  at  bottom  from  two  feet  to 
two  feet  six  inches  and  at  the  top  from  one  foot  to  one  foot  eight  inches.     The 
steel  in  the  same  decks,  as  well  as  that  in  the  downstream  deck,  has  been  re-ar- 
ranged for  the  better,  though  the  amount  used  remains  practically  the  same. 

13.  Cut-off  walls  on  both  upstream  and  downstream  sides  of  the  old  dam 
omitted,  except  for  about  one  hundred  feet  immediately  west  of  the  head  gate 
masonry.     This  was  left  to  the  discretion  of  the  City  Water  Power  Company's 
Engineer  unless  the  City  wished  to  invoke   the   arbitration   clause.     In   the   in- 
stance mentioned,  the  upstream  cut-off  wall  was  not,  in  my  opinion,  carried  two 
feet  into  good  rock  (though  I  was  over-ruled  by  Dr.  Scott,  who  passed  on  it  as 
satisfactory,  because  of  its  impermeability,  as  shown  by  holes  drilled  in  the 
trench  and  attempts  made  to  force  grout  under  pressure  into  it.)     Under  the  toe 
of  this  same  portion  of  the  old  dam,  and  under  the  ragged  break  at  its  west  end, 
a  cut-off  wall  eighteen  inches  thick  (instead  of  two  feet  as  specified)  and  six  feet 


Changes  Made  in  Rebuilding  Dam.  75 

in  height,  was  built  to  protect  the  toe  from  scour,  but  the  material  upon  which  it 
rests  is  soft  enough  to  be  easily  scratched  by  the  finger  nail,  which  was  not,  of 
course,  according  to  specifications. 

18.  The  specifications  require  that  the  proportions  of  material  in  the  con- 
crete shall  be :  one  part  cement,  two  parts  clean  sand,  and  four  parts,  crushed 
stone  or  screened  gravel.     The  engineer  for  the  City  Water  Power  Company  al- 
lowed the  contractors  to  use  pit-run  gravel,  i.  e.,  sand  and  gravel  mixed  as  it 
comes  from  the  river  beach,  getting  the  proper  proportions  by  adding  stone  or 
sand  as  determined  by  taking  voids  by  means  of  water.    Also  keeping  the  voids 
in  the  aggregate  within  certain  limits  by  the  same  means.     An  excess  of  cement 
was  required  and  used  because  of  this  change. 

19.  The  fourth  penstock,  as  required  by  the  specifications,  was  omitted  by 
permission  of  the  City  Council.     First  class  material    was    specified    for    these 
tubes.     Old  ones,  some  of  which  were  badly  pitted  by  rust,  were  used.     Outside 
of  the  Power  House  these  penstocks  were  well  covered  with  reinforced  concrete ; 
inside  of  the  building  on  both  the  inside  and  outside  of  the  pipes  and  outside  of 
the  building  on  the  insides  of  the  pipes,  "smooth-on"  was  used  on  the  joints  and 
defects,  besides  being  coated  with  a  wash  made  of  retempered  cement. 

20.  The  core  wall  was  not  carried  as  deep,  as  high,  nor  as  far  into  the  bank 
as  specified,  but  this  was  passed  upon  by  the  City's  representative  as  being  all 
right  because  of  the  impervious  character  of  the  "adobe"  on  which  it  rests  and 
because  the  head  gate  masonry  was  considered  sufficiently  tight  without  the  pro- 
tecting wall.     The  water  does,  however,  percolate  through  it  in  places  in  small 
quantities. 

21.  The  tail  race  as  described  in  the  specifications  has  not  been  built  up  to 
the  present  time,  this  being  according  to  a  verbal  understanding  among  those 
concerned,  if  certain  conditions  were  met. 

22.  The  pointing  of  the  joints  of  the  masonry  of  the  old  dam  was  not  done 
because  considered  unnecessary  by  the  Engineer   for   the    City   Water   Power 
Company.     The  seepage  at  the  east  end  of  the  old  part  demonstrates  the  neces- 
sity for  pointing  or  grouting. 

(Signed)  S.  S.  Posey, 

Inspecting  Engineer. 

The  City  was  unprepared  to  advance  more  money  until  the  work  was  placed  in 
acceptable  shape,  and  was  unwilling  to  specify  just  what  it  would  require  before  the 
work  would  be  accepted.  The  bond  holders  on  their  part  were  naturally  unwilling 
to  add  more  funds  unless  they  could  be  assured  that  such  additions  would  complete 
the  work  to  the  entire  satisfaction  of  the  City  Council,  and  the  Contractors  were 
obliged  to  make  assignments.  While  the  conditions  have  been  hastily  examined  by 
various  engineers  and  brief  reports  have  been  made  in  the  interest  of  the  bond  hold- 
ers and  various  other  interested  parties,  nothing  has  been  done  toward  completing 
the  plant  for  about  two  years. 


APPENDIX  4 

CONDITIONS  AND  FACTS  ASCERTAINED  DURING  EXAMINATION  BY  DANIEL  W.  MEAD — AUG- 
UST, 1917 

Early  in  July,  1917,  the  writer  was  engaged  by  the  City  of  Austin  to  investigate 
the  conditions  and  to  report  on  the  situation  as  it  now  obtains  at  the  Austin  Dam. 
Before  commenting  on  the  present  plant  and  outlining  the  betterments  which  should 
be  made  in  order  to  place  the  same  in  safe  condition  for  proper  operation  and  main- 
tenance, it  is  necessary  to  review  the  physical  conditions  which  exist  at  the  site  of 
the  works. 

It  is  obvious  that  the  examination  of  a  completed  structure  with  the  water  stand- 
ing 10  to  20  feet  above  the  foundation  is  attended  with  much  difficulty,  and  that  to 
draw  conclusions  from  any  examination  which  can  be  made  under  such  conditions, 
without  incurring  a  prohibitive  expense,  makes  it  necessary  to  depend  largely  on 
the  statements  of  those  who  have  been  in  personal  touch  with  the  work  during  its  con- 
struction, at  the  same  time  checking  up  such  statements  by  comparison  with  those 
made  by  different  witnesses,  and  by  the  facts  that  can  be  definitely  determined.  Pre- 
liminary to  his  examination  the  writer  read  all  of  the  articles  which  he  could  secure 
that  have  been  written  on  the  Austin  dam,  a  list  of  which  is  given  in  a  later  appendix. 

On  reaching  Austin,  the  writer  visited  the  City  office  and  discussed  the  matter  at 
some  length  with  Mayor  Wooldridge,  Superintendent  Bartholomew,  and  the  mem- 
bers of  the  City  Council.  He  also  had  access  to  the  various  letters,  papers  and 
plans  which  are  in  possession  of  the  City.  He  also  discussed  the  matter  in  detail 
with  Mr.  Guy  A.  Collett,  Receiver  for  the  City  Water  Power  Company,  who  placed  all 
plans  and  data  which  he  possessed  at  the  disposal  of  the  writer.  The  writer  also 
secured  considerable  information  from  Mr.  H.  L.  Cobb  who  was  Assistant  Engineer 
in  charge  of  the  grouting  and  other  construction  work.  Mr.  Cobb  furnished  a  large 
album  of  photographs  showing  various  views  taken  during  the  construction  and  at 
various  periods  in  the  work.  Other  views,  especially  of  the  older  work,  were  ob- 
tained from  the  engineering  papers,  the  local  photographers  and  others.  A  number 
of  these  views  are  reproduced  in  this  Report  and  show  clearly  the  conditions  which 
existed  at  various  periods,  which  can  be  clearly  understood  now  only  by  the  informa- 
tion these  views  contain. 

Mr.  S.  S.  Posey,  who  had  been  Inspecting  Engineer  for  the  City  during  the  con- 
struction work,  spent  most  of  his  time  with  the  writer  during  his  stay  in  Austin. 
Mr.  Posey 's  knowledge  of  the  conditions  greatly  facilitated  the  writer's  examination. 
Mr.  Frank  S.  Taylor,  who  was  Resident  Engineer  during  the  construction,  placed  his 
information  and  data  at  the  writer's  disposal,  and  furnished  much  information  of 


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the  conditions  which  developed  during  construction,  and  of  the  foundation  depths  and 
conditions.  This  information  was  quite  indispensable  to  the  conclusions  of  the 
writer. 

Mr.  Frank  S.  Taylor  was  Resident  Engineer  of  the  work  done  under  the  fran- 
chise given  Mr.  William  D.  Johnson.     He  was  in  immediate  charge  of  the  construe- 


FIGUBE  40  —  Sketch  showing  Depth,  Thickness  and  General    Arrangement   of    the    Foundation   Walls. 


tion  from  the  beginning  of  the  work  until  it  was  practically  discontinued  early  in 
1915.  Mr.  Taylor  furnished  the  writer  with  a  series  of  seven  sketches,  copies  of 
which  are  shown  in  Figs.  34  to  40  inclusive,  which  sketches  show  in  general  the 
depth  to  which  the  foundation  walls  were  taken,  and  the  thickness  and  general  ar- 
rangement of  such  walls.  Mr.  Taylor  also  furnished  a  detailed  memorandum  con- 
cerning the  holes  drilled  for  the  purpose  of  grouting  the  foundation,  and  the  results 
of  the  grouting,  which  throws  much  light  on  the  conditions  of  the  bottom  as  deter- 
mined during  construction.  He  also  furnished  a  blueprint  plan  of  the  foundations, 
showing  the  location  of  all  grout  holes,  which  (with  some  additions)  is  reproduced  in 
four  sections,  shown  in  Figs.  41  to  44,  pages  82  to  85  inclusive. 


Foundation  Conditions.  81 

MEMORANDA   CONCERNING  THE   FOUNDATION  CONDITIONS  OF  THE  AUSTIN  DAM  FROM 
SKETCHES  AND  DATA  FURNISHED  BY  MR.  FRANK  S.  TAYLOR 

Concerning  this  work,  Mr.  Taylor  says: 

*  *  The  attached  logs  of  drill  holes  and  subsequent  grouting  operations  in  the 
Austin  Dam  are  approximately  correct.     The  lines  showing  the  probable  direc- 
tion of  permeable  parts  of  the  foundation  are  indicated  as  follows: 
"All  foundations  east  of  No.  44,  impermeable. 

"Possible  permeable  lines  thru  dam  foundation  as  indicated  by  numbered 
holes  on  the  'Grout-hole  Chart':— 44  to  68,  59  to  98,  78  to  117,  81  to  108,  136  to 
153,  141  to  165,  152  to  166,  159  to  180,  171  to  182,  210  to  208,  223-228  to  236,  242 
to  247,  252  to  261,  255  to  263,  271  to  S.  W.,  277  to  S.  W.  (These  'possible  per- 
meable lines'  have  been  indicated  by  lines  on  the  diagram,  shown  on  pages 
82  to  85  inclusive.  D.W.M.) 

' '  Nearly  every  hole  in  the  cut-off-wall  foundation  which  proved  to  be  in  per- 
meable strata,  was  found  to  be  in  permeable  strips,  bounded  by  more  or  less  defi- 
nite lines  running  parallel  to  a  South  West  direction  thru  it. 

* '  The  lake  was  filled  while  operations  were  still  in  progress  on  the  spillway. 
There  was  then  a  cofferdam  across  the  river  down  stream ;  a  4,000,000  gallon  per 
day  pump  working  less  than  half  of  the  time  kept  out  all  water  from  the  coffer- 
dam until  the  water  ran  over  the  dam  at  elevation  151.  At  this  time,  however, 
the  flow  of  the  river  at  the  rapids,  about  1000  feet  below  the  dam,  indicated  that 
about  three  times  as  much  water  was  flowing  there  as  was  pumped  out  of  the 
coffer. ' ' 

This  last  statement  would  seem  to  indicate  that  while  there  was  little  seepage 
under  the  dam,  and  rising  inside  the  cofferdam,  that  about  twice  this  amount  was 
rising  as  springs  in  the  river  below  the  cofferdam  and  above  the  rapids  referred  to. 
In  the  following  pages,  abstracts  have  been  made  of  the  records  of  the  grout 
holes  through  which  a  considerable  amount  of  grout  was  forced  into  the  foundation. 
The  grouting  work  was  done  by  means  of  a  grouting  cylinder  under  pneumatic 
pressure.  The  cylinder  was  18"  in  diameter  and  42"  in  height,  connected  with  an 
Ingersoll-Band  air  compressor  with  an  intervening  air  receiver  of  about  100  cubic 
feet  capacity  (see  Fig.  45,  page  99.)  Mr.  Taylor  says: 

"General  Scheme  of  Tests. — It  was  decided  to  make  the  holes  first  grouted 
24  feet  apart.  It  was  assumed,  and  afterwards  did  develop,  that  the  grout 
would,  in  many  cases,  go  from  one  hole  to  another  through  crevices  and  between 
strata  of  limestone.  After  the  adjacent  24  feet  holes  were  grouted,  another 
hole  was  drilled  midway  between  these  two,  making  the  holes  12  feet  apart.  The 
log  of  this  intermediate  hole  was  carefully  watched,  as,  from  the  indications 
found  in  the  drilling,  we  could  determine  where  grout  had  sealed  all  crevices  be- 
tween the  two  holes  24  feet  apart.  If,  as  in  many  cases,  we  found  that  there 
were  some  crevices  which  were  not  filled  by  either  one  of  the  first  two  holes,  the 


82 


Report  on  the  Dam  at  Austin,  Texas. 

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grouting  machine  was  placed  on  the  intermediate  holes,  and,  in  fact,  our  prac- 
tice was  to  place  the  grouting  machine  on  this  intermediate  hole  even  if  we  found 
no  indication  of  permeability.  In  some  locations  it  was  found  that  even  this 
short  space  was  not  sufficiently  close  together  to  satisfy  us,  and,  in  such  cases, 
other  holes  were  bored  between  the  12  foot  spacings  and  the  operation  just  de- 
scribed repeated,  reducing  the  distance  to  6  feet  apart.  In  a  few  cases  we  found 
that  holes  between  the  6  foot  borings  were  necessary  to  give  us  a  satisfactory 
evidence  of  impermeable  foundation. 

''Auxiliary  Holes  Under  and  Between  Diaphragm  Walls. — A  great  many 
holes  were  bored,  as  shown,  only  5  feet  deep,  but  these  holes  were  bored  on  the 
downstream  side  of  the  cutoff  wall,  which  has  been  made  impermeable,  as  al- 
ready described,  and  the  purpose  of  the  5  foot  holes  was  to  determine  only  the 
solidity  of  the  foundation  for  bearing  our  walls.  In  a  great  many  cases,  water 
was  found  in  these  shorter  holes,  and  wherever  the  findings  of  the  drill  indicated 
a  cavity  or  seam,  that  hole  was  grouted  in  exactly  the  same  manner  as  if  it  were 
in  the  cutoff  wall.  It  is  probable,  however,  that  all  of  the  water  that  developed 
in  the  shorter  holes  came  from  downstream  pressures,  the  mouth  of  all  of  these 
holes  being  from  8  to  15  feet  below  the  level  of  the  water  on  the  downstream  side 
of  the  lower  cofferdam. 

"On  the  Downstream  Side  of  the  Old  Dam. — A  number  of  holes  were  bored 
on  this  part  of  the  structure,  as  shown  on  the  chart,  and  the  grouting  machine 
was  placed  on  same  for  the  purpose  of  testing  the  permeability  of  the  strata  un- 
der the  toe  of  the  dam,  but  little  grout  was  forced  into  these  holes,  the  testing 
being  done  with  water  only.  In  two  or  three  holes  the  test  proved  that  there  was 
a  permeable  strata  under  the  toe  of  the  western  end  of  the  old  dam,  but  our  op- 
erations afterwards,  on  the  upstream  side  of  this  same  section,  comprehended 
the  entire  length  of  the  dam  and  to  a  depth  of  12  feet,  so  that  there  is  every  rea- 
sonable indication  that  the  grouting  hereinafter  described  filled  cavities  that 
were  discovered  by  the  tests  on  the  downstream  side  of  the  old  dam." 

In  the  abstract  of  the  record  of  the  grout  holes,  shown  on  plans  Figs.  41  to  44 
(see  pages  82  and  85)  are  given: 

1st.  The  number  of  hole. 

2d.  El.,  the  elevation  referred  to  a  horizontal  plane  160  feet  below  the  crest 
of  the  dam,  or  approximately  100  feet  below  the  average  low  water  level. 
3d.  "D",  the  depth  of  the  drill  hole  below  the  elevation  given;  and 
4th  The  amount  of  grout  forced  into  the  hole,  indicated  in  cubic  feet. 

The  grout  was  a  mixture  of  one  part  of  cement  and  two  parts  of  fine  screened 
sand,  with  water  to  make  a  grout  of  creamy  consistency  (each  charge  from  the  cyl- 
inder being  equal  to  about  2  cubic  feet  of  grout).  The  word  "attempt"  is  used  to  ex- 
press each  separate  operation  of  the  grouting  machine.  The  records  of  all  holes 
that  took  no  grout  are  omitted  from  this  abstract : 


Record  of  Drilling  and  Grouting.  87 


ABSTRACT  OF  RECORD  OF  DRILLING  HOLES  AND  GROUTING 

(NOTE — The  numbers  serve  to  locate  the  position  of  each  hole  on  the  Grouting  Charts) 

40.  Elevation  86;  depth  12  ft.;  no  cavities.  First  attempt  blew  grout  out  in 
trench  at  lower  level  about  Station  22.  Later,  second  attempt  showed  oozing  of 
grout  in  side  of  trench  above  top  of  hole,  stopped  during  discharge.  Third  at- 
tempt, refusal. 

44.  Elevation  82;  depth  11  ft.  in  cracked  rock.  Two  inch  cavity  at  4th  foot;  37 
full  discharges  of  grout  forced  into  pipe.  Crack  extended  across  cutoff  wall  from 
northeast  to  southwest  and  was  from  14"  to  6"  wide.  The  37th  charge  filled  all 
crevices  to  refusal. 

54.  Elevation  81  y>;  9  ft.  hole;  2  ft.  in  soft  rock;  cavity  for  iy2  feet  then  4y2 
feet  of  good  rock ;  then  about  one  foot  of  soft  rock ;  balance  •  hard  rock.  First  at- 
tempt discharged  grout  through  crevices.  Several  charges  attempted  with  thicker 
grout  evidently  discharging  through  crevices.  Later,  y2  charge  oozed  through  crev- 
ices and  cracks  stopped. 

58.  Elevation  81  feet;  10y2  ft.  hole;  5"  cavity  in  5th  foot;  soft  rock  9th  foot; 
balance  solid.     First  attempt  forced  grout  through  crevices  at  pier  footings  between 
diaphragm  walls  5  and  6,  about  70  ft.  from  No.  58.     Twenty-two  full  charges  were 
put  in  before  refusal. 

59.  Elevation  81  ft.;  depth  10  ft.     Water  appeared  at  4th  foot;  soft  rock  at  6th 
and  7th  foot;  balance  good  rock.     First  attempt  forced  water  and  grout  to  surface 
in  the  vicinity  of  hole.     Nine  charges  put  in  before  refusal. 

61.  Elevation  81  ft.;  depth  8  ft.;  soft  rock  in  3d,  4th  and  7th  foot;  balance  good 
rock  and  grout.  Four  full  charges. 

64.  Elevation  81  feet;  depth  9  feet.  One  foot  of  soft  rock.  One  foot  of  soft 
rock  in  7th  foot.  Six  full  charges ;  7th  attempt  discharged  grout  in  vicinity  of  No. 
72  and  filled  holes  Nos.  65  and  66.  Later,  after  grouting  Nos.  70,  71  and  72,  made 
8th  attempt  nearly  full  discharge.  Total  about  7  charges. 

68.  Elevation  81;  depth  11  ft.;  Sy2  ft.  good  rock  and  grout;  6"  soft  rock;  balance 
good.  Continuous  grouting  for  about  25  hours.  Forty-eighth  charge  showed  indica- 
tions of  grout  all  along  line  of  crevice  encountered  at  No.  44,  also  at  No.  65  and  No. 
66.  Fifty-six  full  charges  before  refusal. 

NOTE. — Operations  from  No.  44  to  No.  69  were  evidently  contiguous  to  the  crack 
described  in  No.  44,  which  follows  the  general  direction  of  the  larger  fault  lines  of 
the  Balcones  fault  zone.  The  fault  lines  found  in  the  limestone  across  the  river  at 
the  dam  are  nearly  vertical,  and,  with  the  exception  of  this  crevice  and  one  described 
as  crossing  the  cut-off  wall  at  about  Station  8  +  25',  the  lines  are  cracks,  which  evi- 
dently do  not  change  the  solidity  of  the  stone,  nor  cause  a  break  in  the  lines  of  stra- 
tification. 


88  Report  on  the  Dam  at  Austin,  Texas. 

72.  Elevation  81  ft. ;  depth  Sy2  ft.  in  good  rock  and  grout  except  one  crack  in 
4th  foot.  First  and  2d  charge  forced  grout  through  crevice  near  by.  Later  20 
charges  put  in;  23d  attempt,  refusal. 

76.  Elevation  81 ;  depth  5  ft.,  when  drill  stopped  in  crack.  Good  rock.  Grout 
came  into  this  hole  from  No.  78.  Hole  piped  above  footing  course  of  wall  No.  6 
later.  First  attempt  forced  grout  around  footing  near  by;  second  attempt  took  full 
charge;  third  attempt,  refusal. 

78.  Elevation  81 ;  depth  10  ft.  Soft  spot  in  6th  and  8th  foot.  Third  attempt 
forced  water  from  Nos.  76  and  77.  Thirteenth  attempt  forced  air  through  crevices 
at  about  No.  73 ;  with  41  full  charges,  all  crevices  filled  to  refusal. 

90.  Elevation  82 ;  depth  10  ft.  Cavities  and  soft  rock  in  7th,  8th,  9th  and  10th 
foot;  balance  good.  First  attempt  blew  air  and  water  in  No.  89;  second  attempt 
showed  at  No.  108 ;  6th  attempt  stopped  indications  at  108 ;  water  again  running  from 
108  and  oozing  nearby  after  7th  attempt.  Grout  still  going  in  with  16th  charge; 
17th  charge  oozed  nearby  and  in  excavations  for  Nos.  7  and  8  diaphragm  walls ;  28th 
charge  forced  water  and  red  mud  25  feet  south  of  hole ;  35th  attempt  forced  grout 
through  crevices ;  36th  attempt  still  forcing  air  out  of  trenches  of  diaphragm  walls 
Nos.  6  and  7.  Same  conditions  with  47th  attempt;  54th  attempt  showed  clean  grout 
forced  from  every  place  where  air  had  been  noted ;  63  full  charges  put  in  with  prob- 
able loss  of  about  10  per  cent. 

92.  Elevation  81 ;  depth  10  ft. ;  solid  rock  and  grout  except  7th  foot  which  was 
soft  and  cavity.  Sixth  charge  showed  water  running  freely  through  crack  nearby; 
llth  attempt  spouted  water  and  grout  in  foundation  of  diaphragm  wall  No.  10  and 
forced  air  through  crevices  in  No.  9  diaphragm  wall;  40th  attempt,  refusal;  48 
charges  put  in. 

95.  Elevation  81 ;  depth  10  ft. ;  8th  and  9th  foot  soft ;  balance  good  rock.  First 
attempt  blew  grout  and  water  out  of  No.  96 ;  5y2  charges  put  in. 

98.  Elevation  80  ft. ;  depth  10  ft. ;  5th,  6th  and  7th  foot  soft ;  balance  good  rock. 
First  five  charges  forced  air  and  water  through  No.  101 ;  8th  attempt,  refusal ;  total 
8  charges. 

108.  Elevation  82^  feet;  10  ft.  hole.     Eock  seamy  but  hard;  3  charges  put  in. 

117.  Elevation  83 ;  10  ft.  hole ;  solid  rock  except  crack  in  2d  foot  and  soft  rock  in 
9th  and  10th  foot ;  7  full  charges  put  in  with  nearly  full  charge  and  refusal  at  8th 
attempt. 

136.  Elevation  8£y2  ft. ;  11  ft.  hole  in  solid  rock  except  soft  spot  in  7th  foot.  First 
attempt  forced  water  through  crevices;  4  charges  before  refusal. 

141.  Elevation  84y2  ft.;  depth  lift.  First  8  feet  solid,  then  iy2  feet  soft;  bal- 
ance good.  Second,  3d  and  4th  charges  blew  yellow  mud  from  145a,  and  water  and 
grout  continued  to  flow  from  145a  with  7th  and  8th  attempts ;  10th  to  18th  attempts 
forced  grout  and  water  through  148.  Nineteenth  and  20th  attempt  forced  grout 
from  No.  144;  pipe  at  144  then  plugged.  Thirty-first  attempt,  refusal.  About  27 
full  charges. 


Record  of  Drilling  and  Grouting.  89 

147.  Elevation  84;  11  ft.  hole.  Soft  spot  in  2d,  5th  and  7th  foot;  balance  good 
rock.  At  5th  foot  water  flowed  from  hole ;  nearby  water  was  flowing  from  crevice  in 
rock  in  which  a  3"  pipe  had  been  cemented,  confining  the  flow  from  crevice  to  said 
pipe.  First  11  charges  each  forced  water  out  of  3"  pipe ;  12th  charge  forced  grout 
from  3"  pipe,  and  the  latter  was  plugged.  The  23d  charge,  plug  removed  from  3" 
pipe.  Grout  going  in  slowly  with  the  58th  charge.  Sixty-third  attempt  refusal. 
Machine  moved  to  3"  pipe  with  refusal  at  first  attempt.  Total,  62  charges. 

153.  Elevation  83.  This  hole  was  one  of  the  core  bore  holes  made  previously 
by  the  City  of  Austin,  being  No.  19  on  chart  herewith  (see  page  54).  Depth  about 
20  ft.  This  hole  was  in  foundation  of  diaphragm  wall  No.  16,  and  the  water  was 
piped  up  and  the  wall  concreted.  Water  rose  in  pipe  to  water  level  (outside  coffer). 
First  attempt,  full  charge ;  afterwards  charges  were  put  in  rapidly  without  appreci- 
able resistance  until  pipe  was  full;  157  charges. 

155.  Elevation  85;  11  foot  hole;  in  good  solid  rock  except  soft  in  8th  and  9th 
foot.  First  attempt  forced  grout  from  around  footing  and  in  pump  sump  at  north 
end  of  diaphragm  wall  No.  17.  Thirteenth  attempt,  all  blew  out  at  sump.  Stopped 
at  this  point  because  all  grout  was  lost.  Probably  about  net  12  charges. 

160.  Elevation  85  feet.     Cemented  pipe  in  crevice  at  this  location.    Put  in  41 
charges  when  cofferdam  failed  and  water  covered  the  hole.    After  break  in  coffer, 
refusal  at  43d  attempt ;  total  43  charges. 

161.  Elevation  85;  5  ft.  hole  in  good  rock  except  cavity  and  soft  spot  in  4th  foot. 
First  5  attempts  forced  grout  from  crevice  in  all  directions  within  radius  of  15  feet. 
Forced  water  and  mud  from  No.  167  and  grout  at  20th  charge.    After  plugging  No. 
167,  refusal  at  77th  charge;  total  about  75  charges. 

166.  Elevation  86 ;  depth  5y2  feet.  Water  bearing  sand  in  4th  foot ;  balance  solid ; 
4th  attempt  forced  air  and  water  to  crevice  in  lower  end  of  trench  of  No.  18  diaph- 
ragm wall.  Second  and  3d  attempts  filled  all  crevices  and  forced  grout  from  No. 
180;  total,  11  charges  before  refusal. 

171.  Elevation  87;  depth  Iiy2  feet.  Four  feet  hard  rock;  iy2  ft.  soft;  then  2y2 
ft.  solid  followed  by  iy2  feet  soft  rock;  balance  good  rock.  First  7  attempts  dis- 
charged water  and  mud  from  No.  162  and  in  various  nearby  crevices.  Hole  cleaned 
and  left ;  later,  successive  attempts  after  the  8th  showed  same  indications ;  18th  at- 
tempt forced  water  from  173.  Indications  of  permeability  decreased  and  practically 
stopped  at  about  40th  charge.  Total  43  charges. 

177.  Elevation  87;  depth  43,4  ft.  Solid  rock  with  seam  at  3y2  ft.  depth.  Grout- 
ing in  this  hole  showed  increase  of  water  in  Nos.  179,  178,  184,  183,  182  and  181.  This 
hole  took  19  full  charges  before  refusal. 

179.  Elevation  86^;  depth  5  ft.;  solid  rock  but  water  flowed  from  the  hole. 
Three  holes  were  drilled  in  this  vicinity,  water  flowing  from  each  one.  The  flow  was 
greater  after  subsequent  blasting  of  trench  foundations;  evidently  the  water  in  all 
of  those  holes  came  from  the  same  seam.  First  charge  showed  grout  coming  up  in 
No.  182;  total  of  22  full  charges. 


90  Report  on  the  Dam  at  Austin,  Texas. 

182.  Elevation  87y2.  This  was  one  of  the  holes  mentioned  in  No.  179;  10  full 
charges  before  refusal. 

187.  Elevation  88.  This  hole  was  piped  up  through  footing  of  diaphragm  wall 
No.  20.  Took  12  charges,  after  which  grout  began  to  flow  from  seams  near  footing. 
Seams  were  calked  and  later  5  more  charges  were  forced  into  the  hole.  This  caused 
grout  to  show  in  No.  186.  Total  of  17  charges  before  refusal. 

210.  Elevation  S9y2.  Near  this  hole,  water  coming  from  crevices  in  foundation 
nearby,  also  water  coming  into  cofferdam  through  large  hole  about  elevation  90. 
First  charge  at  low  pressure  and  charges  continued.  Grout  color  showing  from 
various  crevices  even  to  a  distance  of  120  feet  to  the  big  pump  sump  hole.  Moved 
grouting  machine  at  about  the  90th  charge  to  No.  214,  then  back  to  No.  210 ;  then 
moved  to  No.  192  which  took  no  grout ;  then  back  to  No.  210 ;  with  total  of  115  charges, 
springs  stopped  and  the  big  hole  was  bailed  out  by  hand. 

212.  Elevation  S9y2 ;  depth  10  ft. ;  good  rock.  Put  in  11  charges  when  it  was 
evident  that  grout  was  being  forced  out  of  nearby  crevices  as  fast  as  put  in.  Three 
days  afterwards,  another  attempt  was  made  without  success.  Second  attempt,  re- 
fusal. 

214.  Elevation  91 ;  depth  11  ft.  Good  rock  except  soft  in  7th  foot.  Five  charges 
put  in,  blowing  out  at  213  and  near  210.  After  grouting  No.  210  several  days  after, 
machine  was  again  put  on  No.  214  with  refusal  at  4  different  attempts. 

222.  Elevation  92;  depth  Iiy2  feet;  8ft.  solid  rock,  then  1  foot  soft;  then  2y2 
feet  solid  rock.  Took  10  full  charges  before  refusal. 

225.  Elevation  92 ;  depth  ll1/^  feet.  Solid  rock  except  soft  in  8th  foot.  Water 
flowing.  Three  full  charges. 

226  Elevation  92 ;  depth  12  feet ;  solid  rock.  Water  seam  about  10th  foot.  Hole 
took  47  full  charges. 

229.  Elevation  92 y2.  This  was  one  of  the  bore  holes  made  by  the  City  some 
years  ago.  First  charge  forced  grout  into  No.  228  which  had  not  yet  been  grouted, 
and  in  No.  231,  and  showed  air  bubbles  within  a  radius  of  10  or  12  feet.  First  few 
charges  stopped  all  leaks.  Eleven  full  charges  put  in. 

232.  Elevation  92y2.     No  log  of  drilling.     Took  17  full  charges. 

235.  Elevation  toe  of  old  dam;  about  9  foot  hole;  5  feet  in  grout  and  4  feet  in 
limestone  and  mortar.     Poured  in  water  and  it  ran  through  the  hole.     Put  on  grout- 
ing machine  and  it  took  one  full  charge ;  afterwards    10    charges ;    later    about    y% 
charge;  total  10y>  charges. 

236.  Elevation  toe  of  old  dam.     Depth  about  4y>  feet.     Water  ran  freely  through 
hole;  took  12  full  charges  without  showing  any  indications  from  outside  or  in  water 
below  the  dam.     Thirteenth  charge  blew  out  through  the  joints  in  the  granite  nearby. 
After  cleaning  the  hole  and  plugging  the  joints,  replaced  machine  and  the  hole  took 
nearly  one  full  charge  before  refusal.     Total  about  13  charges. 


Record  of  Drilling  and  Grouting.  91 

242.  Elevation  93y2 ;  11%  ft.  depth.  Solid  rock  except  slight  drop  19th  foot. 
Water  flowed  freely  from  hole.  First  few  charges  blew  out  in  No.  244  and  evidently 
forced  grout  around  No.  240,  because  water  began  to  flow  from  that  hole  although 
it  had  previously  been  grouted.  This  flow  finally  stopped.  The  vicinity  of  this  hole 
was  covered  with  mud  and  the  operations  were  conducted  with  care,  observing  all 
possible  leaks  of  grout.  After  a  few  charges,  all  indications  of  bubbling  in  the  water 
or  color  of  grout  ceased.  Ninety-three  full  charges ;  then  refusal. 

.243.  Elevation  93y2;  depth  Iiy2  ft.  Solid  rock  except  soft  spot  in  8th  foot. 
Water  flowed  freely  from  hole  and  showed  bubbles  in  crevices  about  60  feet  up- 
stream. Charges  went  in  without  indications  of  leak  after  the  first  2  or  3  up  to  the 
37th,  when  grout  came  through  No.  245.  Plugged  this  pipe  and  continued  until  47 
charges  had  been  put  in. 

244.  Elevation  94 ;  depth  11  ft.  Solid  rock  with  soft  spot  in  8th  foot.  Twenty- 
four  full  charges  were  put  into  this  hole  under  maximum  pressure  for  each  charge. 

246.  Elevation,  toe  of  the  dam;  depth  11  ft.  Total  of  two  charges  before  re- 
fusal. 

255.  Elevation  95 ;  depth  11%  ft.  Solid  rock  except  soft  in  the  8th  foot  and  last 
foot.  Air  and  water  forced  in  this  hole  proved  it  to  have  outlets.  First  few  charges 
with  no  surface  indications.  This  hole  grouted  to  refusal  with  60  full  charges. 

258.  Elevation  about  95;  depth  11  ft.  Two  full  charges  and  then  grout  blew 
through  crevices  around  hole ;  4  additional  charges  were  probably  largely  lost ;  prob- 
ably about  3  full  charges. 

260.  Elevation  95;  depth  11  ft.     Solid  rock  except  soft  places  in  9th  and  10th 
foot.     Took  7  full  charges  with  no  indications  of  leaking  nearby. 

261.  Elevation,  toe  of  old  dam.     Depth  11  y2  ft.  in  granite,  limestone  and  mortar. 
Last  foot  soft  material.     Water  ran  freely  through  this  hole  and  93  charges  were 
placed  without  evidence  of  loss.    Grout  was  forced  in  with  light  pressure  except  last 
few  charges.    Final  refusal  at  80  pounds  pressure. 

263.  Elevation  below  toe  of  dam.  About  11  foot  hole  in  granite,  limestone,  mor- 
tar and  flint.  First  few  charges  showed  leaks  nearby  which  finally  ceased.  Took 
43  full  charges. 

271.  Elevation  95%  feet.  Depth  about  18%  ft.;  6%  ft.  solid  rock;  one  foot 
water  bearing,  soft ;  balance  rather  soft  but  solid.  Water  rose  when  drill  reached 
about  8  feet.  Fourteen  charges  put  into  this  hole  under  maximum  pressure  of  70 
pounds. 

276.  Elevation  about  96 ;  depth  11%  ft. ;  7  ft.  solid  rock,  then  one  foot  cavity ; 
afterwards  3%  feet  of  solid  rock.  This  hole  when  tested,  evidently  had  openings  un- 
derneath the  dam,  shown  by  bubbles  in  water  below  toe  of  the  old  dam — reported  by 
laborers  afterwards.  This  hole  took  a  number  of  charges,  probably  25,  without  max- 
imum pressure,  after  which  charges  were  put  in  with  gradually  increasing  pres- 
sure. Total  of  57  charges  put  in  with  refusal. 


92  Report  on  the  Dam  at  Austin,  Texas. 

277.  Elevation  about  96 ;  depth  about  10  ft. ;  4  ft.  solid  rock  and  about  y2  ft.  soft 
rock  or  clay ;  then  5  ft.  of  limestone.  Water  leaked  away  rapidly.  Grout  forced  at 
about  y2  maximum  pressure  up  to  20th  charge.  Put  in  27  charges,  the  last  at  about 
60  pounds  pressure.  Breakdown  in  machine  stopped  operations  and  before  resump- 
tion concrete  had  set  in  the  cracks.  Number  278  was  then  drilled  which  took  about 
y2  of  a  charge. 

NOTES  BASED  ON  INFORMATION  FURNISHED  BY  MR.  S.  S.  POSEY 

(Mr.  Posey  was  Inspecting  Engineer  for  the  City  of  Austin,  beginning  his  work  at 
the  Dam  some  time  after  excavation  had  begun  but  before  the  first  concrete  was 
poured.  He  began  his  inspection  about  October  20,  1912.) 

The  information  furnished  by  Mr.  Posey  was  of  much  value,  and  for  the  pur- 
pose of  this  Report  has  been  abstracted  as  follows: 

The  structure  now  constituting  the  Austin  (Texas)  Dam  consists,  in  its  western 
portion,  of  about  500  feet  of  the  original  structure,  built  in  1893,  560  feet  of  the  new 
structure,  built  under  the  contract  of  1911;  and  on  the  east  of  about  60  feet  of  the 
original  1893  structure,  also  the  original  head  works  and  a  core  wall  extending  about 
300  feet  east  from  the  east  end  of  the  spillway.  The  so-called  core  wall  consisted 
of  a  narrow  concrete  wall,  built  in  excavation,  north  of  and  adjacent  to  the  original 
head  work  masonry  and  extending  easterly  therefrom.  From  the  west  end  of  the 
head  work  masonry  the  bottom  of  the  cut-off  wall  dropped  downward,  holding  a 
depth  of  approximately  two  feet  below  the  rock  bottom  or  about  one  foot  below  the 
cross  walls  of  the  dam. 

Cross  Walls. — The  cross  walls  (i.  e.  the  walls  at  right  angles  with  the  face  of 
the  dam)  are  numbered  from  the  east,  the  one  at  the  end  of  the  new  work  being 
number  0. 

In  general,  the  trenches  for  the  cross  walls  of  the  dam,  penetrated  the  surface 
rock  approximately  one  foot.  Walls  4,  5, 6,  7,  8,  9  and  10  were  built  in  trenches  ex- 
cavated to  an  extra  depth,  wall  8  being  the  deepest  and  extending  down  22  feet  below 
low  water.  Beyond  wall  8  the  condition  of  the  rock  of  the  bottom  improved  in  qual- 
ity somewhat  and  the  cross  walls  were  carried  to  a  less  depth.  At  wall  18  and  be- 
yond, the  excavation  for  the  cross  walls  was  made  with  pot  shots.  The  depth  below 
low  water  to  the  rock  surface  being  about  12  feet  at  wall  18  and  sloping  upward  to 
a  depth  of  9  feet  at  wall  27.  From  wall  18  to  wall  27  the  cut-off  wall  was  carried 
down  below  the  surface  of  the  rock  about  two  feet.  From  wall  15  to  wall  27  the  gen- 
eral slope  of  the  foundation  rock  is  down  stream  and  is  about  two  feet  in  the  width 
of  the  dam.  The  cut-off  wall  was  carried  westward  to  the  end  of  the  new  work  and 
no  further  and  no  cut-off  wall  was  placed  either  at  the  heel  or  toe  of  the  west  portion 
of  the  old  dam. 

A  curtain  wall  about  18  inches  in  thickness  and  6  or  7  feet  in  depth  was  carried 
from  the  head  gate  masonry  westward  along  the  toe  of  the  east  portion  of  the  old 


Leakage.  93 

dam  underneath  the  new  construction  and  underneath  the  broken  end  of  the  old  dam 
until  it  encountered  the  cross  wall  of  the  new  construction. 

Leakage. — Near  the  east  end  of  the  west  portion  of  the  old  dam  for  about  80 
feet,  the  grout  that  was  forced  into  the  11  ft.  holes  under  80  Ibs.  pressure  came  out 
of  the  old  dam  masonry  joints  at  the  first,  second,  third  and  possibly  the  fourth 
joints  above  the  foundation. 

On  the  toe  of  the  west  portion  of  the  old  dam  a  number  of  two  inch  holes  were 
drilled  through  the  masonry  and  to  a  depth  of  about  11  ft.  Water  came  through  the 
toe  from  some  of  these  holes.  Air  forced  into  some  of  these  holes  at  perhaps  60  to 
70  Ibs.  pressure  appeared  in  the  drill  holes  above  the  dam  and  in  the  cracks  of  the 
foundation  rock.  Water  also  rose  and  overflowed  through  a  hole  drilled  into  the 
face  of  the  dam  about  8  feet  above  the  toe. 

With  the  lake  full,  water  seeps  around  the  west  end  of  the  old  dam  through  the 
rock  and  appears  as  seepage  on  the  face  of  the  bluff  to  a  point  perhaps  ten  feet  be- 
low the  top  of  the  dam  and  springs  apparent  along  the  bluff  for  a  distance  about  100 
feet  below  the  dam.  Evidence  of  leakage  into  the  natural  rock  on  the  east  side  of 
the  river  was  found  at  the  following  points: 

1st.  Under  the  new  forebay  wall,  in  the  dry  wall  of  the  old  forebay  and  east 
of  the  northerly  end  of  the  boom. 

2d.  Under  the  masonry  of  the  City  wharf  about  200  feet  north  of  the  dam. 
3d.  In  Walsh's  Slough  near  the  northerly  end  of  an  old  clay  dam  which  was 
constructed  by  Mr.  Walter  Johnson  to  save  water  during  the  operation  of  the 
old  plant. 

4th.  In  the  upper  end  of  the  Taylor  bluff,  perhaps  a  half  mile  north  of  the 
dam. 

It  is  Mr.  Posey's  belief,  from  the  direction  of  the  opening  from  hole  number 
one,  that  the  "corewall"  was  not  carried  deep  enough  to  cut  off  the  water  from  this 
source.  However,  an  opening  under  the  westerly  penstock,  now  in  place,  was  cut 
off  by  the  "corewall." 

From  the  various  openings  above  described  and  perhaps  from  many  others  not 
definitely  located,  a  considerable  amount  of  water  seeped  into  the  east  bluff  above 
the  dam  and  appeared  as  springs  and  seep  water  at  various  points  for  nearly  a  half 
mile  below  the  dam.  Some  of  these  points  may  be  described  as  follows : 

1st.  A  small  pipe  near  the  north  end  of  the  retaining  wall.     This  flows  very 
strong  at  full  lake  and  is  now  dry  with  water  at  elevation  16. 

2d.  A  small  pipe  under  the  north  draft  tube  which  flows  full  at  full  lake  but 
is  now  stopped. 

3d.  A  2-inch  pipe  built  into  the  wall  facing  the  bluff  and  between  the  two 
south  turbines  which  also  flows  full  at  full  lake  level. 

4th.  The  head  gate  masonry  also  shows  seep  water  to  a  considerable  height 
above  the  ground. 


94  Report  on  the  Dam  at  Austin,  Texas. 

5th.  There  is  also  seepage  through  the  face  of  the  rock  at  the  south  end  of 
the  power  house. 

6th.  In  springs  which  show  on  the  river  face  of  the  foundation  wall  near  the 
south  end  of  the  power  house,  south  of  the  present  draft  tubes.     At  full  lake  this 
spring  required  a  3-inch  centrifugal  pump  to  take  care  of  it  while  building  the 
concrete  blocks  at  the  ends  of  the  draft  tubes,  and  the  water  is  still  flowing  with 
the  lake  level  at  elevation  16. 

7th.  Seepage  through  joints  in  the  clay  bank,  beginning  about  200  feet  south 
of  the  dam,  and  extending  1000  feet  or  more  in  a  southerly  direction. 

8th.  Seepage  also  appears  in  the  form  of  springs  in  three  draws  south  of  the 
dam,  the  strongest  one  being  the  one  farthest  south  from  the  dam,  which  flows 
approximately  8  to  12  second  feet.  The  next  strongest  one  was  about  one- 
fourth  mile  northward  toward  the  dam,  which  flows  strong  enough  to  rapidly 
erode  the  east  bank. 

Between  these  two  springs  the  water  came  out  in  the  alluvial  field  about  30  feet 
above  the  river  to  a  sufficient  extent  to  destroy  a  crop  of  cantaloupes  for  a  market 
grower. 

The  south  spring  issued  first  from  an  opening  in  the  rock  20  feet  above  the  river, 
and  later  appeared  at  an  elevation  about  10  feet  lower.  None  of  this  water  appeared 
until  about  a  month  after  the  water  in  the  lake  rose  to  the  higher  levels. 

Leak  Under  the  Dam. — As  previously  noted  the  walls  of  panels  4  to  10  were 
carried  to  an  extra  depth  on  account  of  the  poor  condition  of  the  foundation  rock. 
After  the  construction  and  filling  of  the  dam  a  leak  appeared  in  the  sixth  panel  of  the 
new  dam  about  5  feet  down  stream  from  the  cut  off  wall,  and  near  the  east  side  of  the 
intermediate  wall.  As  the  flow  from  this  was  very  large  (perhaps  30  second  feet), 
an  attempt  was  made  to  close  off  this  leak.  The  running  water  had  thrown  up  a  bank 
of  sand,  gravel  and  mud  across  the  bay  to  near  the  surface  of  the  water  and  a  coffer 
dam  was  constructed  by  driving  Wakefield  sheet  piling  into  this  deposit  from  the 
east  wall  of  the  bay  to  the  east  side  of  the  intermediate  pier.  A  4-inch  centrifugal 
pump  and  motor  were  installed.  The  water  did  not  rise  after  the  construction  of 
the  cofferdam  nor  was  the  pump  able  to  lower  the  water,  although  it  was  speeded 
up  and  was  attached  to  a  powerful  motor.  A  diver  who  examined  the  opening  found 
that  it  was  of  sufficient  size  so  that  he  could  stand  in  the  opening  and  the  surface  was 
about  level  with  his  arm  pits.  From  this  position  he  said  he  could  reach  the  cut-off- 
wall.  He  also  stated  that  the  water  appeared  to  come  from  a  downstream  direction 
and  impinge  against  the  cut-off  wall. 

An  earth  cofferdam  was  built  immediately  opposite  the  position  of  this  leak  on 
the  upstream  side  of  the  cutoff  walls  and  atove  the  dam.  The  water  in  this  cofferdam 
could  easily  be  lowered  and  there  was  evidently  no  direct  connection  through  the 
rock  under  the  cut-off  wall. 


Leakage.  95 

The  opening  in  the  rock,  where  the  leak  appeared,  was  filled  with  sacks  of  sand 
which  were  also  piled  on  top  with  the  intent  to  throttle  the  flow  so  that  the  cofferdam 
could  be  pumped  out.  After  which  the  leak  broke  out  about  ten  feet  southwest,  near 
the  edge  of  the  cofferdam,  coming  up  through  the  fill,  indicating  a  continuation  of  the 
rock  fissure  in  that  direction.  The  work  was  then  stopped. 

After  the  reservoir  had  been  filled  and  when  it  was  lowered  to  furnish  water  to 
the  rice  growers  near  Bay  City,  while  its  surface  was  falling  rapidly,  a  strong  flow  of 
air  and  water  mixed  appeared  about  halfway  between  Huch  and  Wright's  boat- 
house  and  the  mouth  of  Bee  Creek.  It  was  so  strong  that  a  good  sized  motor  boat 
could  not  be  held  over  it,  the  boat  each  time  being  swept  quickly  aside.  The  flow  was 
strong  enough  to  raise  the  surface  of  the  water  two  or  three  inches  above  the  sur- 
rounding water.  After  about  24  hours  this  flow  stopped  and  another  flow,  not  so 
strong,  appeared  about  100  feet  above  the  dam  near  the  west  end  of  the  new  portion. 
This  stopped  after  about  half  a  day.  In  Mr.  Posey  's  judgment  this  indicated  that  a 
cavern  or  underground  passage  was  being  emptied  when  the  head  was  reversed  by 
the  lowering  of  the  lake  level  or  that  the  air  and  water  had  been  confined  in  a  cavern 
and  the  pressure  was  strong  enough  to  overcome  the  head  of  water  above  its  out- 
let. 

There  was  also  a  spring  near  some  sheet  piling  about  walls  17  and  18,  about  30 
feet  from  the  cut-off  wall,  both  during  construction  and  when  the  water  in  the  reser- 
voir was  lowered. 

During  the  work  on  the  leak  in  panel  six  the  water  was  clear  and  much  cooler 
than  the  water  in  the  river  but  later  with  a  slight  rise  in  the  river  making  the  water 
of  the  stream  murky  the  water  from  the  leak  appeared  to  be  of  the  same  color. 

Seepage  in  the  Old  Dam. — Near  the  east  end  of  the  west  portion  of  the  old  dam, 
where  the  new  work  joins  it,  the  breaking  away  of  the  portion  of  the  original  struc- 
ture, washed  out  by  the  1900  flood,  shelled  away  the  granite  facing  so  that  at  the 
break  one's  arm  could  be  thrust  between  .it  and  the  limestone  core.  The  mortar 
joints  were  broken  in  places  also,  so  that  now  when  the  water  in  the  lake  is  standing 
at  51  ft.  or  higher,  the  spillway  face  of  the  old  dam  is  kept  constantly  wet  for  a  dis- 
tance of  about  125  ft.  on  a  line  which  slopes  to  the  west.  The  highest  part  is  only 
5  or  6  ft.  below  lake  level  and  the  lowest  part  in  the  neighborhood  of  10  ft.  above  low 
water.  The  masonry  above  the  toe  is  wet  constantly.  These  conditions  show  that 
the  limestone  core  of  the  gravity  section  is  quite  porous.  Another  evidence  of  the 
porosity  of  the  masonry  of  the  old  dam  is  the  fact  that  water  stands  only  a  few  feet 
below  the  lake  level  in  the  most  easterly  one  of  the  six  inch  well  holes  drilled  through 
the  dam  from  top  to  bottom  and  at  lower  levels  in  the  other  two. 

Class  of  Work. — The  class  of  work  in  general  done  by  the  sub-contractor  was 
good  but  very  rough  as  to  finish.  The  forms  were  not  held  rigid  to  position,  partic- 
ularly as  to  the  crest  gate  piers,  and  consequently  trouble  was  experienced  in  get- 
ting the  crest  gates  fitted  to  place  in  the  openings ;  a  great  deal  of  chipping  was 


96  Report  on  the  Dam  at  Austin,  Texas. 

found  necessary  because  of  the  swelling  of  the  pier  forms.  The  trenches  for  the  foot- 
ings of  the  supporting  walls  were  filled  with  concrete  entirely,  thus  sealing  all  exca- 
vations of  this  character  and  helping  to  prevent  scouring  by  the  flood  waters.  Mr. 
Posey  does  not  consider  that  the  cut-off  wall  trench  and  some  of  those  for  the  trans- 
verse walls  were  carried  deep  enough  for  safety  at  various  points,  although  the  depth 
was  approved  by  the  City's  representative. 

Cofferdams. — Sand  and  rock  cofferdams  were  used  to  exclude  the  water  from  the 
underwater  work.  These  were  easily  destroyed  by  slight  rises  in  the  river  and  were 
partially  or  entirely  rebuilt  thirteen  times. 

General  Amount  of  Pumping. — A  ten-inch  centrifugal  pump  and  a  twelve  inch 
dredge  pump  of  the  same  type  usually  handled  the  water,  but  on  one  occasion  an  eight 
inch  was  needed  in  addition.  A  large  pulsometer  was  all  that  was  needed  in  the  cut- 
off wall  trench  in  most  cases,  but  sometimes  a  smaller  one  of  the  same  type  and  a 
four-inch  centrifugal  were  also  needed. 

Grouting. — The  plan  of  grouting  relied  upon  to  cut  off  the  flow  of  water  in  the 
foundation  of  the  dam  was  carried  on  conscientiously  and  as  continuously  as  possi- 
ble. In  one  instance  at  least  it  was  not  effective,  and  Mr.  Posey  thought  at  the  time 
the  work  was  being  done  that  some  of  the  soft  material  in  the  cavities  and  between  the 
hard  strata  was  simply  being  compressed.  If  water  managed  to  percolate  through 
it,  a  larger  opening  could  easily  be  made  by  it  when  under  flood  head.  That  cones  of 
grout  were  formed  around  the  grout  pipes  was  demonstrated  by  holes  drilled  through 
the  grout  after  it  had  hardened,  but  Mr.  Posey  believes  that  inverted  cones  of  com- 
pressed mud  were  also  formed  between  them.  In  other  cases  he  thinks  the  grout 
followed  the  irregular  cavity .  where  it  was  free  to  do  so. 

Concrete. — The  concrete  was  supposed  to  be  a  1 :2 :4  mix  with  the  aggregate  sep- 
arated. The  engineers  for  the  City  Water  Power  Co.  saw  fit  to  change  this  to  a 
mixed  aggregate  with  stone  or  sand  added  as  shown  to  be  needed  by  voids  deter- 
mined by  means  of  water.  If  the  percentage  of  voids  ran  about  24  or  25  per  cent.,  the 
material  was  considered  all  right.  This  aggregate  ran  up  to  2  and  2y2  inches  and 
down  to  the  finest  sand.  Four  sacks  of  cement  were  used  in  each  yard.  Mr.  Posey 
considers  the  concrete  mostly  good  above  elevation  100,  but  below  that  some  of  it  did 
not  test  out  as  it  should  have  done  though  this  was  probably  offset  by  the  increase 
in  thickness  of  footings  and  the  courses  immediately  above  them.  The  upstream 
deck  was  made  water  tight  by  the  use  of  hydrated  lime,  and  this  showed  exception- 
ally tight  for  all  heads  of  water. 

Reinforcing. — The  reinforcing  was  carried  out  closer  to  plans  than  Mr.  Posey 
ever  saw  attempted  in  large  work  of  this  character  and  he  believes  the  structure  to  be 
sufficiently  reinforced  to  withstand  every  strain  to  which  it  may  be  subjected  unless  the 
flood  water  head  should  be  increased.  The  only  walls  not  strongly  reinforced  are 
the  cross  walls  supporting  the  dam  on  the  inside.  The  bars  are  used  here  princi- 
pally around  openings.  These  walls  are  not  bonded  well  to  the  .spillway  deck  and 


Conduct  of  the  Work.  97 

make  it  desirable  to  repair  the  remainder  of  the  sluiceway  arches  so  that  these  walls 
will  not  get  strong  pressure  from  the  inside  when  the  sluiceways  are  in  use.  The 
water  rises  inside  the  dam  to  nearly  the  30  ft.  level  at  these  times. 

Power  House  Foundations. — Considerable  blasting  and  digging  were  required  to 
get  the  old  foundations  of  the  power  house  out  of  the  way.  Some  of  them  had  to  be 
taken  down  to  the  level  of  the  granite  wall  and  these  and  the  stone  bluff  were  blasted 
off  about  four  feet  for  the  space  occupied  by  the  new  turbines.  The  space  under  the 
old  wooden  floor,  where  space  was  not  needed,  was  filled  and  a  concrete  floor  built  on 
top  of  this  fill.  No  change  was  made  in  the  foundation  of  the  part  of  the  old  building 
left  standing.  Thirty-three  feet  were  added  to  the  length  of  the  house. 

Tail  Race. — The  tail  race  was  not  built  according  to  plans,  but  was  made  an 
open  channel  about  fifty  feet  wide  on  the  bottom  with  a  depth  of  five  feet  below  low 
water  at  the  end  next  to  the  draft  tubes  and  three  feet  below  the  same  level  at  its 
river  end.  An  attempt  was  made  to  wash  it  out  with  the  water  from  the  turbines 
but  without  success.  Two  rises  partially  obstructed  the  channel  with  rock  and  drift 
and  in  both  instances  the  draft  tubes  were  blocked  so  that  the  turbines  could  not  be 
used. 

Penstocks  and  Draft  Tubes. — The  penstocks  and  draft  tubes  were  built  mostly 
out  of  the  old  tubes  installed  about  1893,  the  elbows  where  the  penstocks  connect  to 
the  turbine  chambers  and  the  elbows  in  the  draft  tubes  being  new.  The  penstocks 
were  protected  on  the  outside  of  the  building  by  a  covering  of  wire  mesh  and 
concrete  but  not  on  the  inside  of  the  power  house.  They  were  also  treated  with 
smooth-on  and  a  wash  of  retempered  cement.  No  leaks  of  consequence  appeared 
during  the  test  in  these  pipes,  but  on  account  of  a  failure  at  first  to  provide  large 
enough  air  relief  pipes  the  one  on  the  east  side  collapsed  under  the  north  building 
wall  and  for  about  30  feet  each  side  of  it.  The  pipe  was  jacked  into  shape  and  large 
relief  pipes  added.  The  draft  tubes  had  to  be  recalked  at  the  test  to  get  a  proper 
vacuum  and  at  last  some  of  the  leaks  were  stopped  with  Portland  cement. 

Conduct  of  the  Work. — The  sub-contractor  agreed,  so  Mr.  Posey  was  told,  to  carry 
out  the  work  according  to  a  certain  scheme  laid  down  before  the  work  was  started, 
and  on  this  account  the  excavation  was  commenced  on  the  higher  levels  in  the  core 
wall  trench  when  the  river  conditions  were  exceptionally  favorable  for  work  in  the 
river.  The  delay  caused  the  river  work  to  go  over  into  two  unusually  wet  years 
when  flood  conditions  were  very  bad  and  made  the  work  drag  along  for  two  years 
longer  than  it  should  have  done.  No  equipment  for  rapid  excavation  was  on  hand 
except  two  cableways,  and  this  part  of  the  work  was  slow.  Concrete  was  first  laid 
in  wall  No.  17  which  was  where  the  rock  was  first  exposed.  The  entire  foundation 
area  was  not  exposed  to  inspection  except  the  position  upon  which  the  walls  actually 
rested.  The  footing  forms  for  wall  No.  17  were  sunk  in  the  sand  by  digging  out  on 
the  inside.  The  concrete  had  to  be  underpinned  afterwards.  The  rock  for  two  panels 
east  of  wall  No.  17  was  washed  fairly  clean  by  sluicing  and  that  in  the  "Gap"  be- 


98  Report  on  the  Darn  at  Austin,  Texas. 

tween  walls  No.  17  and  No.  27  was  also  cleaned,  but  sand  afterwards  covered  the 
lower  portions  and  the  forms  had  to  settle  into  it.  In  all  other  cases  the  trenches 
were  dug  for  the  footings  and  such  mateiial  as  could  be  piled  up  in  the  spaces  be- 
tween them  was  so  disposed  of. 

DISCUSSION  OF  CONDITIONS  BELCW  THE  TOE  OP  THE  PRESENT  DAM 

It  is  apparent  that  the  conditions  of  the  river  bottom  below  or  downstream  from 
the  toe  of  the  dam  were  not  investigated  tither  before  the  construction  of  the  original 
dam  in  1890-93  or  prior  to  the  reconstruction  in  1911-15. 

The  eastern  part  of  the  original  dam  was  constructed  in  a  wide  trench  excavated 
through  the  alluvial  deposit  that  occupied  more  than  the  east  half  of  the  original  can- 
yon of  the  ancient  Colorado  River  (see  Fig.  15,  page  45  and  Fig.  16,  page  45).  This 
deposit  below  the  dam  was  gradually  removed  by  the  flood  waters  which  were  also 
known  to  be  seriously  eroding  the  rock  below  the  dam,  for  these  floods  were  con- 
stantly adding  to  the  pile  of  rock  which  had  formed  below  the  dam  and  which  is 
clearly  shown  in  Fig.  23,  page  52. 

In  spite  of  this  gradual  accumulaticn,  which  could  come  from  no  other  place 
except  from  the  river  bottom  immediately  below  the  dam,  the  City  apparently  made 
no  soundings,  and  the  condition  remained  unknown  except  from  a  cursory  examina- 
tion made  by  Prof.  T.  U.  Taylor  who  states  (see  W.  S.  &  I.  Paper  No.  40,  page  46) 
that  he  made  certain  soundings  from  the  toe  of  the  dam  in  March  1899,  and  at  or  near 
the  point  where  the  break  in  the  dam  afterwards  occurred,  was  unable  to  reach  the 
bottom  at  9.5  feet  below  the  water  surface.  Prof.  Taylor  further  says  (ibid  page 
47): 

"During  a  freshet  in  1892  the  overfall  cut  through  this  hard  strata,  tore  up 
large  pieces  (some  of  them  10  feet  long, 4  feet  wide,  and  2.5  feet  thick  and  of  7  to 
8  tons  weight),  and  deposited  a  whole  quarry  in  a  confused  and  irregular  pile 
about  150  to  200  yards  farther  down  the  river.  These  stones  remained  in  that  lo- 
cation until  the  big  freshet  of  June  7,  1899,  when  they  were  carried  away." 

Prof.  Taylor  further  describes,  in  this  same  pamphlet,  the  conditions  observed 
by  Mr.  J.  G.  Palm  in  1897,  as  shown  by  Fig.  19,  page  49. 

On  the  destruction  of  the  old  dam  in  1900,  the  space  below  the  dam  was  again 
filled  by  detritus  from  the  old  structure  ard  by  the  formation  of  bars  of  sand  and 
silt;  hence  on  the  reconstruction  of  the  dem  in  1911,  this  space  was  again  covered 
(Figs.  46  and  47).  The  toe  of  the  west  portion  of  the  old  dam  was  also  covered  by  a 
deep  deposit  of  silt  (see  Fig.  48)  so  that  the  condition  there  was  unknown  as  will 
be  noted  from  the  fact  that  Messrs.  Davis,  Hill  and  Taylor,  in  their  report  of  1908 
assumed  that  the  toe  of  this  section  had  also  been  undermined,  for  they  show  how 
repairs  should  be  made  for  such  a  condition  (see  A  Fig.  27,  page  56). 

These  areas  were  again  uncovered  by  the  floods  that  passed  over  the  dam  in  1915 
and  subsequently.  On  the  writer's  visit,  soundings  were  taken  below  the  entire  struc- 


Conditions  below  Dam. 


FIGURE  45 — Grouting  Rock  behind  West  Portion  of   Old  Dam.     Bottom  Apparently  not 

Exposed  for  Inspection. 


FIGURE  46 — New  Dam  as  Completed  1915,   Showing  Fill  below  Apron. 


Report  on  the  Dam   at  Austin,   Texas. 


FIGURE  47 — New  Dam  Nearing  Completion  1915,  Showing  Fill  below  Apron. 


FIGURE  48 — New  Dam  after  Completion  1915,  Showing  Fill  below  Apron. 


Conditions  below  Dam. 


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Conditions  below  Dam.  105 

ture.  The  results  of  these  soundings  are  shown  by  Figs.  49  to  52,  pages  101  to  104,  in- 
clusive, the  location  of  which,  relative  to  the  dam,  can  be  determined  from  the  pier 
numbers  on  the  dam. 

From  these  soundings  it  will  be  noted  that  the  rock  below  the  west  half  of  the 
structure  is  still  intact,  and  that  the  toe  cf  this  section  never  had  been  undermined 
by  the  flood  waters.  On  the  other  hand,  the  bedrock  below  the  new  structure  had 
been  deeply  eroded  by  the  flood  waters  over  the  old  dam,  and  perhaps  during  the 
subsequent  failure.  This  investigation  shows  that  with  very  few  exceptions  the  rock 
bottom  in  front  of  the  new  section  of  the  dam  is  considerably  below  the  foundation  of 
the  piers  or  cross  walls.  This  fact  will  also  be  seen  more  clearly  perhaps  from  the 
following  table  which  shows  the  elevation  of  the  piers  or  cross  walls  at  the  front  of 
the  new  dam,  the  lowest  elevation  of  the  low  point  in  the  rock  in  front  of  the  pier, 
and  the  relation  of  the  rock  -f  (above)  or  -  -  (below)  the  dam  foundation. 

EELATIVE  ELEVATIONS  OF  DAM  FOUNDATION  AND  BOCK  IN  FRONT  OF  TOE 

Belation 

No.                                   Pier  Elevation  Bock  Elevation  —  Lower 

+  Higher 

0   90  80                              —10 

1    88.8  82                               —  6.8 

2    88.5  82                               —  6.5 

3    88.5  84                               —  4.5 

4   84.5  81                               —  3.5 

5    84.5  81                               —  3.5 

6    83.4  83.5                           —     .1 

7    83.4  82                               +  1.4 

8   80.8  84                               +  3.2 

9    82.2  84.5                           +  2.3 

10  83.5  84  +     .5 

11  84.5  79.2  —  4.3 

12  84  83  —     .1 

13  85  84.5  —     .5 

14  87.2  82  —  5.2 

15  87.25  83  —  4.25 

16  86.9  84  —  2.9 

17  86  84.5  —  1.5 

19  87.4  85  —  2.4 

21  86.7  85  —  1.7 

23 87.4  86  —  1.4 

From  this  table  it  will  be  noted  that  with  the  exception  of  piers  8,  9,  and  10,  which 
are  below  the  rock  bottom,  all  of  the  remaining  piers  are  from  .5  foot  to  10  feet  above 


106  Report  on  the  Dam  at  Austin,  Texas. 

the  lowest  point  in  the  rock  bottom  immediately  in  front  of  the  piers.  This  condition 
is  shown  by  comparison  of  the  diagrams  furnished  by  Mr.  Taylor  and  shown  on  pages 
77  to  80,  with  the  diagrams  of  the  soundings  shown  on  pages  101  to  104.  Two  of  the 
worst  conditions  are  illustrated  by  the  A.  and  B.  Fig.  12,  page  28. 

GEOLOGICAL  AND  PHYSICAL  CONDITIONS  AT  THE  DAM  SITE 

To  what  extent  the  conditions  at  the  dam  site  were  appreciated  by  geologists  at 
the  time  of  the  original  construction  in  1890-93  is  unknown,  but  it  seems  doubtful  if 
any  adverse  comment  was  then  made  as  to  the  location.  It  is  a  fact  that  the  influence 
of  such  conditions  on  the  safety  of  such  structures  was  not  as  well  recognized  at  that 
date  as  at  present,  and  it  is  probably  true  that  no  professional  advice  from  geologists 
concerning  the  advisability  of  the  location  was  sought. 

Following  the  date  of  the  construction  of  the  original  dam,  the  Austin  area  was 
examined  in  detail  by  the  geologists  of  the  United  States  Geological  Survey,  and  in 
May,  1902,  the  Survey  published  a  report  on  the  Austin  quadrangle,  in  which  the  gen- 
eral conditions  in  this  district  were  outlined  in  considerable  detail.  Previous  to  this 
publication,  Messrs.  Eobert  T.  Hill  and  T.  Wayland  Yaughn  had  prepared  an  elab- 
orate article  on  the  "Geology  of  the  Edward's  Plateau  and  Bio  Grande  Plain  adja- 
cent to  Austin  and  San  Antonio,  Texas,  with  Reference  to  the  Occurrences  of  Under- 
ground Waters. ' '  This  was  published  in  1898  as  a  paper  in  Part  II  of  the  18th  An- 
nual Report  of  the  Director  of  the  U.  S.  Geological  Survey  for  the  year  1896-1897. 
The  general  geology  of  this  district,  as  a  part  of  the  Black  and  Grand  Prairie  Region 
of  Texas,  was  also  discussed  in  an  elaborate  monograph  prepared  by  Dr.  Robert  T. 
Hill,  which  was  published  in  1901  as  Part  VII  of  the  21st  Annual  Report  of  the  Di- 
rector of  the  U.  S.  Geological  Survey  for  the  year  1899-1900. 

These  various  publications  have  set  forth  in  considerable  detail  the  conditions 
which  obtain  at  Austin  and  vicinity,  and  have  made  available  data  sufficient  to  show 
the  great  difficulty  of  attaining  safe  construction  at  the  present  site  of  the  Austin 
dam. 

This  dam  site  is  located  on  the  Colorado  River  where  the  river  discharges  from 
the  deep  canyon  of  the  Edward's  Plateau  into  the  shallow  valley  of  the  Black 
Prairie  Region.  The  strata  of  the  Edward's  Plateau,  which  begins  a  mile  or  more 
above  the  dam  site,  are  firm  and  horizontal,  and  the  stream  in  this  section  flows  over 
ledges  of  firm  and  solid  rock,  which  would  probably  make  a  suitable  and  stable  foun- 
dation for  dam  construction.  Within  the  area  on  which  the  dam  is  located  and  east 
of  the  plateau  region,  the  strata  are  joint  ed  and  faulted,  and  constitute  what  is 
known  to  geologists  as  the  Balcones  Fault  Zone.  A  section  along  the  south  side  of 
the  Colorado  River,  showing  the  general  extent  and  displacement  resulting  from 
these  faults,  is  reproduced  in  Fig.  3  page  14,  and  a  map  showing  the  geographic 
location  of  the  principal  fault  lines  in  the  vicinity  of  Austin  is  shown  by  Fig.  2  page 
13. 


Geological  Conditions.  '•.•  ,Jj)  lt)7 


FIGURE  53 — West  River  Bluff  below  Dam  showing  Nature  of  Rock. 


FIGURE  54— Minor  Block  Fault  on  the  North  Side  of  Bee  Creek  near  the  Mouth  and 

Adjacent  to  the  Austin  Dam. 


• 

1  08 


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'«    : 

Report  on   the  Dam  at  Austin,   Texas. 


FIGURE  55 — One  of  the  Group  of  Mormon  Springs. 


FIGURE  56 — Rock  Outlet  where  Mormon  Spring  is  said  to  Discharge  with  High  Water  in  Reservoir. 


Geological  Conditions.  109 

The  geological  formation  in  the  bed  of  the  stream  within  this  area  is  quite  dif- 
ferent from  that  in  the  canyons  of  the  Edward's  Plateau.  Here  the  bedrock  con- 
sists of  the  Edward's  formation  exceedingly  porous  and  soluble,  while  in  the  canyons 
above,  the  strata  are  less  soluble  and  more  durable.  Subterranean  waters  acting 
on  the  Edward 's  limestone  have  resulted  in  caverns  and  crumbling  strata  even  where 
the  surface  rock  is  apparently  solid  and  durable. 

In  the  Walsh  quarries,  about  1000  feet  from  the  dam  site,  was  formerly  an  open- 
ing into  a  cavern,  which  was  said  to  be  quite  extensive.  Mr.  A.  C.  Blanton,  who  su- 
pervised the  borings  at  the  dam  site  in  1908,  visited  this  cavern  at  about  that  date, 
and  in  a  letter  to  the  Engineering  News  (Aug.  22,  1915)  makes  the  statement  that 
this  cavern  extends  southwesterly  nearly  to  the  dam  site  and  probably  under  the 
river.  Others  state  that  it  extends  south  easterly  toward  the  capitol.  The  shaft 
leading  to  the  cavern  was  covered  with  quarry  strippings  at  the  time  of  the  examina- 
tion by  the  writer,  and  its  exact  location  was  unknown.  In  any  event,  it  indicates  the 
cavernous  nature  of  the  rock  closely  adjoining  the  dam  site. 

Similar  indications  are  furnished  by  the  voids  found  by  the  drill  in  the  borings 
of  1908  (see  Fig.  26,  page  54)  and  are  evidenced  by  the  washout  under  the  head- 
works  in  1893  (see  Fig.  17,  page  46)  and  by  the  spring  (see  Fig.  21,  page  51)  which  was 
cut  off  by  the  corewall  constructed  by  the  City  Water  Power  Company. 

The  weak  condition  of  the  bed  joints  and  the  vertical  fissures  in  the  strata  imme- 
diately above  the  river  bed  and  below  the  location  of  the  dam,  are  shown  in  Fig. 
53,  page  107 ;  and  the  general  condition  of  the  faults  may  be  judged  from  the  photo- 
graph of  the  minor  block  fault  which  may  be  seen  on  the  northerly  side  of  Bee  Creek 
near  its  outlet  into  the  Colorado  River,  shown  on  page  107. 

The  main  fault  planes  extend  in  a  vertical  direction  hundreds  of  feet  below  the 
surface  and  cut  the  water  bearing  strata  of  the  lower  geological  deposits.  Deep  ar- 
tesian springs  of  great  volume  and  pressure  well  up  through  the  joint  planes  and 
fissures  in  this  formation.  The  Mormon  Spring,  about  one  mile  north  of  the  dam  site 
and  on  a  fault  line  that  passes  under  or  close  to  the  dam,  is  a  conspicuous  example 
of  such  springs.  This  spring  apparently  discharges  through  various  outlets  from  the 
same  fissure,  according  to  the  stage  of  the  river,  and  the  resistance  of  the  overlying 
alluvial  deposits.  In  August,  1917  several  springs  of  this  group  were  seen  of  which 
Fig.  55,  page  108  is  one.  When  the  water  is  raised  by  the  dam,  the  discharge  is  said 
to  occur  higher  and  higher  up  the  hill,  at  the  same  time  reducing  in  quantity,  and  at 
the  reservoir  full  stage  is  said  to  discharge  through  the  fissures  shown  in  Fig.  56, 
page  108. 

Barton  Spring,  used  as  a  bathing  pool,  is  still  better  known  to  the  citizens  of 
Austin.  Its  discharge,  varying  from  15  to  20  cubic  feet  per  second,  occurs  through 
cracks  and  fissures  that  are  readily  visible  in  the  adjacent  rock  bank  of  the  spring 
and  through  the  clear  water  on  the  bottom  of  the  pool.  (See  Figs.  58  and  59,  page 
111.)  These  waters  undoubtedly  come  from  the  source  tapped  by  the  artesian  wells 


110 


Report  on  the  Darn  at  Austin,  Texas. 


of  Austin,  and  originate  from  the  outcrops  and  percolating  waters  which  reach  these 
water  bearing  deposits  at  and  near  their  outcrop  on  the  western  edge  of  the  Edward's 
plateau.  These  springs  occur  at  the  points  on  the  fault  lines  where  the  weakest 
conditions  exist,  and  doubtless  many  minor  springs  occur  along  such  lines  in  the 


FIGURE  57 — Section  through  Panel  No.  6  of  the  New  Dam  Showing  Possible  Condition  of  Leak. 

gravels  of  the  river  and  below  the  river  surface,  but  are  of  such  small  volume  as  to 
be  unknown  or  unnoticed. 

The  site  of  the  dam  across  the  river  is  almost  at  right  angles  with  one  of  the 
most  conspicuous  of  the  fault  lines,  and  the  unfortunate  condition  in  the  east  half  of 
the  foundation  results.  The  water  encountered  in  the  foundation  of  the  original 
dam  (see  page  44)  and  in  the  present  construction  (see  page  71)  was  probably  from 
this  source,  and  the  low  water  flow  of  the  leak  in  panel  No.  6  below  the  cutoff  wall 
of  the  dam  is  undoubtedly  from  this  source.  When  an  attempt  was  made  by  the 
Receiver,  Mr.  Guy  A.  Collett,  to  investigate  and  repair  this  leak,  the  temperature  of 
the  river  water  was  88°  Fahr.,  while  the  water  from  the  opening  in  the  rock  in  panel 


Geological  Conditions. 


Vii 


FIGURE  58 — View   of  Barton   Spring.     Discharge  Occurs  through   Fissures  in   Rock 

near  Water  Surface. 


FIGURE  59 — Barton  Spring  showing  Fissures  in  the  Rock  Bed. 


*•'*  *  *^0  *  rC^*     0  **  *       >   ^%i 

]  1 2  Report  on  the  Dam   at  Austin,   Texas. 


FIGURE  60 — Rock  from  Foundation  Deposited  below  Dam. 


FIGURE  61 — Rock  from  Foundation  Deposited  below  Dam. 


Geological  Conditions.  1 1 3 

No.  6  was  74°  Fahr.,  and  on  the  same  day  the  water  at  Mormon  Springs  was  73%° 
Fahr.,  and  at  Barton  Springs,  73y2°  Fahr.  These  same  fissures  when  under  pres- 
sure from  the  reservoir  above  the  dam  or  from  the  higher  waters  outside  of  a  cof- 
ferdam are  evidently  capable  of  absorbing  water  under  these  higher  heads,  trans- 
mit it  laterally  and  discharge  it  at  the  lower  levels ;  and  some  of  the  water  encoun- 
tered during  construction  probably  came  from  these  sources.  In  the  investigation 
carried  out  by  Mr.  Collett,  it  was  found  that  when  the  water  above  the  dam  was  al- 
lowed to  rise  6  feet,  the  water  discharged  from  the  fissure  in  panel  No.  6  began  to 
change  in  character,  became  cloudy  and  increased  in  temperature,  showing  that  un- 
der these  conditions  it  was  beginning  to  discharge  river  water.  During  the  writer's 
examination  of  the  dam,  in  August,  1917,  with  about  15  feet  of  water  behind  the  dam, 
the  discharge  was  much  more  turbid  than  the  river  water  below  the  dam,  and  the 
current  from  the  panel  was  visible  for  some  distance  below  the  toe  of  the  dam. 

An  ideal  section  through  Panel  No.  6  and  the  fissure  from  which  the  leak  de- 
veloped, is  shown  by  Fig.  57,  page  110.  The  water  first  broke  through  at  A  and 
under  low  water  conditions  came  up  through  some  line  of  weakness,  AB.  With 
high  water  above  the  dam,  the  fissure  discharged  water  received  into  the  fissure 
from  some  unknown  point  above  the  dam  C,  which  was  transmitted  laterally  through 
the  weak  fissure,  C,  D,  E  at  an  unknown  depth.  When  an  attempt  was  made  to 
check  the  flow  through  A  by  filling  the  opening  with  sacks  of  sand,  etc.,  the  water 
broke  out  to  the  southwest  at  F,  after  which  the  attempt  to  close  the  leak  was  aban- 
doned for  fear  that  conditions  might  be  made  worse  before  more  radical  and  effec- 
tive measures  were  taken. 

It  is  obvious  that  these  fault  lines  must  extend  through  the  dam  foundation  and 
to  hundreds  of  feet  in  depth.  Before  the  development  of  the  fissures  in  panel  No.  6, 
no  spring  of  any  considerable  size  had  developed  at  the  immediate  dam  site,  but  the 
pressure  due  to  a  full  reservoir  gradually  developed  the  weakness  in  this  fault  line 
under  the  narrow  cutoff  wall,  and  has  produced  an  opening  which  connects  with  the 
subterranean  sources  and  also  with  the  reservoir  above  the  dam  at  one  or  more 
points  along  the  fault  line. 

There  appear  to  be  numerous  lines  of  weakness  subsidiary  to  the  principal 
fault  line  under  the  structure  of  the  dam.  During  the  grouting  of  the  foundation, 
the  passage  of  the  grout  for  considerable  distances  along  these  lines  made  them  man- 
ifest, and  those  so  developed  and  noted  are  described  by  Mr.  F.  S.  Taylor  on  page 
81  and  are  shown  by  the  diagonal  lines  on  the  sketches  on  pages  82  to  85. 

The  log  of  the  grout  holes  (see  pages  87  to  92)  shows  that  the  strata  of  the 
foundation  limestone,  at  least  on  the  east  side  of  the  stream,  are  interbedded  with 
clay  so  soft  that  it  was  frequently  expelled  through  the  drill  holes  by  the  grout 
pressure  from  other  holes  where  grouting  operations  were  in  progress.  Much  of 
this  foundation  limerock  is  solid  and  substantial,  but  the  cracks  and  fissures  and  the 
,  interbedded  clay  make  it  liable  to  destruction  from  water  under  pressure  or  at  high 


1  1 4  Report  on  the  Dam  at  Austin,  Texas. 

velocities.  The  condition  of  the  solid  stone  can  be  judged  from  the  blocks  which 
have  already  been  torn  up  from  in  front  of  the  dam  or  under  the  old  dam  at  the  time 
of  its  destruction  and  deposited  500  feet  or  more  below  the  site,  where  much  of  it  still 
remains  (see  Figs.  60  and  61,  page  112.)  The  photograph,  Fig.  62,  page  121,  also 
shows  the  rock  of  the  river  bed  which  was  cleared  at  a  point  just  above  the  junction 
of  the  new  dam  with  the  west  portion  of  the  old  dam  during  the  construction  work. 
The  soluble  nature  of  this  deposit  is  evident  from  the  depression  in  its  surface.  The 
foundation  of  the  new  dam  was,  however,  placed  in  trenches  excavated  several  feet 
below  the  surface  shown. 


APPENDIX  5 

DISCUSSION  AND  CKITICISMS  OP  THE  CONDITIONS  AND  STRUCTURES  OF  THE  PRESENT  IN- 
STALLATION 

Essential  Principles  for  the  Construction  of  Safe  Dams. — The  general  princi- 
ples for  the  construction  of  safe  dams  may  be  briefly  stated  as  follows : 

First. — Dams  must  have  suitable  foundations  to  sustain  the  pressure  transmitted 
through  them. 

The  pressure  which  can  be  safely  applied  to  foundations  varies  with  the  nature 
of  the  material  in  the  foundations.  In  good  practice,  the  allowable  pressures  are 
usually  taken  about  as  follows : 

Tons  per  Sq.  Ft. 

Eock  equal  to  Best  Ashler  Masonry 25  to  30 

Bock  equal  to  Best  Brick  Work 15  to  20 

Bock  equal  to  Poor  Brick  Work 5  to  10 

Clay  in  Thick  Beds — always  dry 4  to    6 

Clay  in  Thick  Beds — moderately  dry 2  to    4 

Second. — Dams  must  be  stable  against  overturning. 

The  resultant  pressures  which  must  be  provided  for  to  safely  fulfill  these  first 
two  principles  should  take  into  account  all  the  forces  which  will  be  active  after  the 
completion  of  the  structure,  and  should  include: 
The  weight  of  the  structure  itself. 

The  pressure  of  the  water  and  silt  impounded  by  the  dam. 
The  upward  pressure  of  water  which  may  seep  under  the  dam. 
The  back  pressure  of  the  tail  water  below  the  dam. 

These  must  be  considered  under  the  most  severe  conditions  which  are  liable  to 
obtain,  and  for  safety  should  answer  the  requirement  that  the  resultant  pressure  of 
all  forces  acting  on  the  dam  shall  pass  within  the  middle  third  of  the  section  in  order 
to  eliminate  tension  in  the  upstream  face  of  the  structure. 

Third. — Dams  must  be  safe  against  sliding  on  their  bases  or  on  any  section  of 
the  dam  itself. 

To  be  safe  from  the  danger  of  sliding,  the  tangent  of  the  angle  made  by  the  re- 
sultant with  a  vertical  line  must  be  less  than  the  coefficient  of  friction  for  the  ma- 
terial. The  coefficient  of  friction  is  about  .7  for  masonry  against  masonry  or  mas- 
onry against  solid  ledge  rock.  This  means  that  for  such  conditions  the  angle  made 
by  the  resultant  with  a  horizontal  line  should  not  be  less  than  55°.  For  a  dam  built 


I  1 6  Report  on  the  Dam  at  Austin,  Texas. 

on  a  foundation  of  clay,  the  coefficient  of  friction  may,  however,  be  as  low  as  .35,  in 
which  case  the  angle  of  the  resultant  with  the  horizontal  should  not  be  less  than 
70°40'.  When,  however,  the  base  of  the  dam  is  built  on  a  rough  and  irregular  solid 
rock  unlaminated  and  not  interbedded  with  clay  seams,  the  shearing  strength  of  the 
rock  is  introduced  and  the  coefficient  of  friction  may  be  regarded  as  increased  to  1.4 
or  more ;  and  if  the  toe  of  the  dam  abuts  solid  rock  that  can  be  maintained  against  the 
erosive  action  of  floods,  even  a  greater  resistance  is  introduced. 

Fourth. — Dams  must  have  sufficient  strength  to  withstand  the  strains  and  shocks 
to  which  they  are  subjected. 

Fifth. — Dams  must  be  practically  water  tight. 

Sixth. — Dams  must  have  essentially  water  tight  connections  with  their  beds  and 
banks,  and,  if  the  bed  or  banks  are  pervious,  with  some  impervious  stratum  below  the 
bed  and  within  the  banks  of  the  stream. 

In  lieu  of  this  requirement,  the  construction  must  be  such  that  any  seepage  be- 
low or  around  the  dam  shall  be  forced  to  travel  such  a  great  distance  that  its  head  is 
used  up  in  friction,  and  its  erosive  power  thus  destroyed. 

Seventh. — Dams  must  be  so  constructed  as  to  prevent  injurious  scouring  of  the 
bed  and  banks  below  them. 

The  application  of  the  above  principles  depends  on  the  material  from  which  the 
dam  is  to  be  built  and  on  local  conditions.  The  important  questions  at  the  Austin  dam 
are:  Have  these  requirements  been  fulfilled '•?  If  they  have  not  been  fulfilled  to  a 
safe  degree,  what  will  be  necessary  to  be  done  in  order  to  secure  safety? 

Foundation  Conditions.  The  foundation  conditions  have  already  been  described 
in  some  detail  and  were  apparently  well  known  to  the  engineers  of  the  City  Water 
Power  Company. 

After  the  closure  of  the  dam,  Mr.  F.  S.  Taylor,  in  the  Engineering  Record  of 
May  29,  1915,  describes  the  foundation  conditions  as  follows : 

"The  river  bed  for  many  miles  up  and  down  stream,  and,  in  fact,  practically 
all  the  underlying  rock  of  the  country,  i  s    limestone,    varying    from    so-called 
"dobe, "  a  disintegrated  limestone,  to  the  hardest  variety.       The  river  bed  is 
seamed  with  fissures,  and  there  are  small  cavities  of  frequent  occurrence,  rang- 
ing from  a  few  inches  to  several  feet  in  largest  dimensions.     These  cavities  are 
encountered  sometimes  as  far  as  20  feet  below  the  surface  of  the  river  bed." 
Again,  in  an  article  in  the  Engineering  News  of  June  3,  1915,  Mr.  Taylor 
writes : 

' '  The  river  bed  and  the  whole  surrounding  country  are  underlaid  with  lime- 
stone, which  has  many  crevices,  seams  and  cavities  at  varying  depths  below  the 
surface.  About  12  years  ago  (?),  two  U.  S.  Government  engineers  made  a  short 
report  for  the  City  of  Austin,  in  which  they  gave  an  adverse  opinion  concerning 
the  character  of  the  river  bottom  for  supporting  a  dam.  About  six  years  ago 


Foundation  Conditions.  1  1  7 

the  City  had  a  number  of  borings  made  to  definitely  determine  the  character  of 
the  river  bed.  It  was  then  found  that  there  were  considerable  amounts  of  broken 
limestone,  soft  limestone,  cavities,  seams  and  fissures  underlying  the  dam,  and 
the  records  obtained  from  these  borings  proved  that  in  order  to  build  a  dam 
across  the  river  at  this  point  the  defects  in  the  strata  underlying  it  would  have  to 
be  corrected.  It  was  decided  to  fill  all  the  underlying  seams  and  cavities  with 
grout,  and  on  the  reconstructed  river  bed  to  build  a  hollow  dam  of  reinforced  con- 
crete of  such  form  that  there  could  be  no  uplifting  force  from  any  leakage  of 
water  under  it.  Furthermore,  as  a  portion  of  this  new  section,  a  cutoff  wall 
would  be  sunk  in  a  trench  cut  in  the  rock  on  the  upstream  side  and  carried  to 
such  a  depth  that  its  lower  edge  would  be  below  all  permeable  strata." 

It  should  be  noted  that  Messrs.  Davis,  Hill  and  Taylor,  the  Government  En- 
gineers referred  to  in  the  above  extract  from  the  Engineering  News,  made  their  re- 
port in  1908  and  had  the  advantage  of  an  examination  of  the  core  drillings  made 
in  that  year  and  which  are  not  now  available,  and  in  the  light  of  such  knowledge 
condemned  the  foundation  at  this  location  as  untrustworthy.  They  advised,  if  this 
location  was  to  be  utilized,  the  construction  of  a  solid  dam,  a  core  wall  20  to  30  feet  or 
more  in  depth  at  the  upper  line  of  the  dam  and  extending  across  the  entire  river, 
and  the  construction  of  a  100  foot  apron  below  the  toe  of  the  old  and  new  sections 
(see  page  56).  Even  with  these  precautions  they  recognized  the  possibility  of  danger 
from  deep  seepage  under  the  dam. 

The  original  specifications  provided  that  the  foundations  below  the  dam  should 
be  made  tight  by  grouting  through  drill  holes  (no  depth  specified)  or  by  some  other 
means  (see  paragraph  7,  page  63).  In  paragraph  8  of  these  specifications  (see 
page  63),  as  well  as  on  the  detailed  drawings  furnished  and  approved  by  the  City's 
representative  in  May,  1912  (Drawing  C-10),  it  was  provided  that  "cutoff  walls 
must  be  carried  at  least  2  feet  into  sound  rock,  which  has  been  shown  by  borings  to  be 
at  least  6  feet  thick."  Both  the  original  and  the  detail  plans  provided  for  a  cutoff 
wall  in  the  bed  of  the  stream  both  above  and  below  the  old  structure.  The  actual 
construction,  as  described  by  Mr.  Taylor  (see  Engineering  News,  June  3,  1915)  was 
quite  different: 

''The  longer  part  of  the  old  masonry  dam,  that  on  the  western  side,  was 
not  protected  by  a  new  cutoff  wall  but  was  grouted  beneath  through  the  test  holes 
which  had  been  drilled  on  the  upstream  side  of  the  section.  The  downstream 
test  holes  were  left  open  as  indicators  of  possible  leakage  and  to  release  any  pos- 
sible upward  pressure  from  such  leakage."  *  : 

"Trenches  were  cut  in  the  rock  to  receive  the  wall  footings,  and  in  the  bot- 
tom of  these  trenches,  at  intervals,  drill  holes  were  made  4  feet  in  depth.  Where- 
ever  these  drill  holes  passed  continuously  through  solid  rock,  the  trench  was  ac- 
cepted as  suitable  to  receive  the  footing.  Wherever  the  rock  was  hard  but  a  cav- 
ity was  encountered,  grout  was  forced  into  the  cavity  and  allowed  to  harden  be- 


1  1 8  Report  on  the  Dam  at  Austin,  Texas. 

fore  the  footings  were  built  upon  it.  Wherever  soft  and  defective  stone  was 
found  below  the  bottoms  of  the  building  trenches,  the  excavation  of  these  trenches 
was  continued  until  some  point  was  reached  below  which  the  thickness  of  the  good 
rock  was  at  least  4  feet. ' ' 

The  deep  cutoff  wall  advised  by  the  Government  Engineers  and  indicated  on  the 
original  drawings,  was  not  constructed  as  noted  in  the  above  quotation,  and  depend- 
ence was  placed  on  grouting  from  shallow  drill  holes.  The  holes  drilled  for  grouting 
were  in  no  case  more  than  12  feet  in  depth ;  although  in  grouting  hole  No.  153,  which 
was  one  of  the  test  holes  (No.  19)  drilled  for  the  City  in  1908  (see  page  89)  and  which 
was  about  20  feet  deep,  314  cubic  feet  of  grout  were  used.  This  amount  was  greatly 
in  excess  of  the  grout  taken  up  by  any  other  hole  in  the  series,  and  clearly  indicated 
the  presence  of  voids  below  the  plane  of  12  foot  grouting. 

The  record  of  drilling  showed  that  not  even  the  four  feet  of  sound  rock  men- 
tioned by  Mr.  Taylor  in  the  above  extract  from  the  Engineering  News  was  present  in 
all  cases.  For  example  the  record  shows: 

Hole  No.    44  2"  cavity  at  4th  foot 

No.    46  2"  cavity  at  4th  foot 

No.    50  Drill  dropped  about  6"  in  3d  foot 

No.    51  Soft  spot  in  3d  foot 

No.    53  Third  foot  soft 

No.    63  Soft  rock  in  2d  foot 

No.    65  6"  soft  rock  in  4th  foot 

No.    66  6"  soft  rock  in  4th  foot 

No.    67  2"  soft  rock  in  2d  foot 

No.    69  6"  soft  rock  in  3d  foot 

No.    79  6"  soft  rock  in  3d  foot 

No.    80  1.5'  soft  rock  in  3d  and  4th  foot 

No.  164  6"  soft  rock  in  3d  foot 

No.  167  Seam  at  3y2  feet 

No.  174  Seam  at  2y2  feet 

No.  177  Seam  at  3V2  feet 

No.  180  Water  seam  at  3  ft. 

No.  201  2  ft.  solid,  8"  drill  dropped,  8"  solid,  6"  soft,  li/2"  solid. 

The  record  of  the  majority  of  the  drill  holes  show  four  feet  or  more  of  solid 
rock.  The  holes,  which  admitted  a  considerable  amount  of  grout,  are  shown  on 
the  diagrams,  Figs.  41  to  44,  pages  82  to  85. 

It  seems  apparent  from  the  reduction  of  the  solid  rock  requirement  from  6  to 
4  feet  that  the  conditions  were  worse  than  were  anticipated. 

Grouting. — Grouting  has  been  extensively  used  for  filling  the  voids  back  of  shaft 
and  tunnel  walls,  both  in  dry  and  wet  work,  and  in  sealing  the  cracks  and  fissures  in 


Grouting  Foundations.  1  1 9 

rock  in  advance  of  shaft  and  tunnel  work  so  as  to  make  the  shaft  or  tunnel  excavation 
through  such  strata  safer  and  less  expensive.  It  has  also  been  used  to  some  extent 
for  similar  purposes  in  dam  foundations  but  apparently  with  less  uniform  success. 
Its  success  depends  on  the  equipment  used,  the  extent  to  which  the  work  is  carried, 
and  the  care  with  which  it  is  done.  While  it  has  been  found  perfectly  feasible  to 
force  grout  into  the  open  spaces  and  voids  of  broken  stone  and  into  the  open  fissures 
and  cracks  in  masonry  and  rock  strata,  it  has  been  found  impracticable  to  force  the 
grout  into  seams  or  voids  filled  with  sand  or  fine  disintegrated  rock  unless  the  sand  or 
other  fine  material  is  first  washed  out,  leaving  the  void  and  cracks  free  and  open. 
The  mere  passage  of  grout  from  one  drill  hole  to  another  does  not  indicate  that  the 
entire  weak  strata  between  the  two  holes  have  been  filled.  Under  pressure  grout  will 
follow  the  line  of  least  resistance  and  will  wash  out  channels  and  passage  along  such 
lines,  appearing  at  considerable  distances  from  the  point  of  entry  and  yet  filling  only 
this  limited  channel,  leaving  other  portions  of  the  strata  in  their  original  condition, 
unfilled  and  still  in  a  dangerous  state.  In  some  of  the  holes,  during  the  Austin  grout- 
ing operations  (see  No.  90  page  88,  also  No.  161  and  No.  171,  page  89),  the  pres- 
sure of  the  grout  forced  soft  clay  from  adjacent  cracks  and  drill  holes,  but  probably 
removed  but  a  small  fraction  of  this  material  which  lies  interbedded  with  the  lime- 
stone of  the  foundation. 

The  grouting  operations  at  the  Austin  dam  are  subject  to  several  criticisms : 
1st.  Only  one  grouting  cylinder  was  used,  and  the  operation  could  not  there- 
fore be  made  continuous,  giving  the  smaller  crevices  a  chance  to  clog  and  hence 
remain  unfilled. 

2d.  The  grouting  at  the  cutoff  was  practically  confined  to  a  single  row  of 
holes  across  the  river,  not  giving  sufficient  breadth  of  the  grouted  zone  to  give 
reasonable  assurance  of  satisfactory  results. 

3d.  The  depths  of  the  grout  holes  were  entirely  too  limited  for  effective  re- 
sults under  the  conditions. 

4th.  The  grout  used  was  a  mixture  of  sand  and  cement,  where,  under  the 
conditions  at  Austin,  the  grout  should  have  been  composed  of  neat  cement  only. 

Concrete,  consisting  of  cement,  sand  and  stone,  is  often  used  for  under  water 
work  when  it  is  deposited  in  mass.  Grout  composed  of  cement  and  sand  is  some- 
times used  for  work  where  only  large  cavities  are  to  be  filled ;  but  where  small  cracks 
and  fissures  are  to  be  filled,  it  is  found  that  if  sand  is  used  in  the  grout  it  is  apt  to 
separate,  to  clog  small  openings  and  to  result  in  imperfect  work.  In  some  cases, 
grout  of  neat  cement  has  been  used  even  when  masses  were  necessary  but  where  the 
separation  of  the  sand  might  endanger  the  results  desired,  as  in  the  case  of  the 
Astoria  tunnel  caisson.  (See  Trans.  Am.  Soc.  C.  E.  Vol.  80,  p.  643,  et  seq.) 

The  ineffectiveness  of  the  grouting  at  the  Austin  dam  is  shown  by  the  large  leak 
that  has  already  appeared  in  panel  six  and  the  smaller  leak  in  panel  four. 


1 20  Report  on  the  Dam  at  Austin,  Texas. 

Deep  Seepage  Under  and  Around  the  Dam. — Section  10  of  the  franchise  ordi- 
nance (see  page  59)  provides  that  Johnson  shall  prevent  or  remedy  leaks  or  seepage, 
through,  under  or  immediately  around  the  end  of  the  dam,  where  such  leaks  shall 
materially  affect  the  use  of  the  water  for  power  purposes. 

It  is  apparent  that,  with  the  reservoir  full  to  the  dam  crest,  a  large  amount  of 
water  leaks  around  the  dam  and  appears  in  the  river  below.  This  condition  is  de- 
scribed at  some  length  in  the  abstract  of  information  by  Mr.  Posey  (see  pages  93  to 
95). 

The  approximate  loss,  with  the  reservoir  full  to  elevation  151,  is  shown  by  the 
following  measurements  made  by  the  U.  S.  Geological  Survey : 

FLOW  DATA  OF  COLORADO  EIVEE  AND  BARTON  CREEK 
(Flows  in  cu.  ft.  per  second) 

Flow  of  Barton    Flow  at  Con-    Inflow  between 

Date,  Flow  at  dam          Creek  gress  Ave.        dam  and  Con-  Remarks. 

1916  bridge  gress  Ave. 

Aug.  29   231  32.9  337  73  4  days  after  reservoir 

was  emptied 

Aug.  31  179      30.5      238       28     6     ditto 

Sept.  2 157      30.1      190       3     8     ditto 

Sept.  6  109      28.2      141       4    12     ditto 

1917 

Feb.  21 236  343  90  Reservoir  filled 

Feb.  23   17 . 2  Assumed    constant 

Flow  at  Barton 
Creek  Feb.  21  to  23, 
inclusive 

NOTE  :  July  9,  1916,  started  to  release  water  from  the  reservoir.  August  26,  reser- 
voir was  emptied  and  normal  flow  allowed  to  pass  dam  until  September  8,  when 
gates  were  closed  and  water  stored,  and  natural  flow  allowed  to  pass  over  crest 
until  released  in  the  autumn  of  1917 ;  1916  discharge  measurements  at  the  dam 
were  made  about  100  feet  above  the  structure,  but  the  discharge  measurement  made 
at  the  dam  on  February  21,  1917,  was  made  just  above  the  rapids  a  few  hundred 
feet  below  the  dam. 
These  measurements  show  that  the  inflow  between  the  dam  and  Congress  Street 

bridge,  eliminating  the  flow  of  Barton  Creek,  was  as  follows : 

With  Reservoir  filled  90  cu.  ft.  per  sec. 

4  days  after  Reservoir  was  emptied  73  cu.  ft.  per  sec. 

6  days  after  Reservoir  was  emptied  28  cu.  ft.  per  sec. 

8  to  12  days  after  Reservoir  was  emptied  3  or  4  cu.  ft.  per  sec. 


Deep  Seepage. 


121 


FIGURE  62— Bed  Rock  above  Dam  near  West  End  of  New  Structure  during  Construction. 


FIGURE  63 — Rock  at  West  End  of  Dam  where  Leakage  occurs. 


22 


Report  on  the  Dam   at  Austin,   Texas. 


FIGURE  64 — Rock  Bluff  below  West  End  of  Dam. 


FIGURE  65 — Pervious  Strata  under  the  Forebay  Wall. 


Deep  Seepage.  1 23 

It  is  possible  that  3  or  4  cubic  feet  of  the  inflow  may  come  from  springs  in  the 
river  bed,  in  which  event  the  losses  from  seepage  around  the  dam  are  apparently 
about  86  cubic  feet  per  second. 

It  is  by  no  means  certain  that  the  above  measurement  represents  the  total  loss 
by  seepage,  especially  with  a  65  foot  head  on  the  dam,  and  it  is  quite  likely  that  some 
of  the  leakage  finds  its  way  into  the  country  rock  away  from  the  river  and  does  not 
augment  the  river  flow  above  the  gaging  station.  It  is  certain  however  that  the  loss 
is  at  least  equal  to  the  above  amount. 

Such  leakage  is  to  be  expected  from  the  geological  conditions  which  have  been 
described,  and  while  these  losses  may  be  reduced  they  can  probably  never  be  entirely 
prevented.  Some  of  this  leakage  undoubtedly  passes  immediately  around  the  dam, 
but  most  of  it  passes  into  the  rock  face  of  the  canyon  walls  for  a  long  distance  above 
the  dam,  and  probably  travels  through  pervious  strata  and  possibly  fissures  far  back 
from  the  end  of  the  dam.  For  the  losses  entering  the  side  walls  at  considerable  dis- 
tances above  the  dam,  the  City  Water  Power  Company  can  not  be  held  accountable, 
under  their  contract  except  as  these  losses  reduce  the  power  output  below  600,000 
horse  power  hours  for  each  30  day  period  as  provided  in  Sec.  11  of  the  franchise  or- 
dinance (see  page  59). 

Leakage  immediately  around  the  dam  occurs  at  the  west  end  of  the  dam  (see 
Fig.  63,  page  121).  Here  even  with  the  head  of  15  feet,  which  obtained  during  the 
writer's  inspection  in  August  1917,  a  considerably  leakage  was  evident.  This  in- 
creases with  higher  heads  and  can  be  followed  for  100  feet  or  more  below  the  dam 
with  the  reservoir  full,  as  reported  by  Mr.  Posey.  From  the  conditions  shown  in 
Fig.  64,  page  122,  it  may  likely  follow  weak  strata  even  to  greater  distances  below 
the  dam. 

Another  loss  which  may  or  may  not  occur  immediately  around  the  dam  is  mani- 
fest in  the  spring  which  issues  under  the  south  end  of  the  power  house. 

The  most  serious  leak  undoubtedly  occurs  through  the  porous  strata  that  gave 
serious  trouble  in  the  original  dam.  The  weak  strata  that  caused  the  washout  under 
the  head  gates  (see  Fig.  17,  page  46),  and  the  leaks  shown  in  Fig.  21,  page  51,  are 
common  to  the  entire  district.  These  strata  apparently  outcrop  on  the  east  rock 
bluff  of  the  river,  both  above  and  below  the  dam,  although  in  general  these  strata  are 
covered  with  soil  and  allvium.  These  porous  strata  absorb  water  from  above  the 
dam  when  the  head  waters  are  raised  above  them.  Through  the  voids,  water  is 
readily  transmitted  and  finds  egress  through  cracks  and  fissures  in  the  strata  below 
the  dam  or  through  the  soil  that  covers  them. 

When  the  old  dam  was  in  use,  serious  losses  of  water  occurred  through  these 
strata,  and  various  abortive  attempts  were  made  to  remedy  this  condition.  One 
of  these  crevices  through  which  the  water  was  known  to  escape  prior  to  1900  is  in 
the  loose  rock  under  the  forebay  wall  (see  Fig.  65,  page  122).  Others  are  in  various 


1 24  Report  on  the  Dam  at  Austin,   Texas. 

outcrops,  presumably  of  these  same  strata,  in  Walsh's  Slough  (see  Fig.  73,  page  131) 
and  at  other  known  points  described  by  Mr.  Posey.     (See  page  94.) 

The  Structure  of  the  Old  Dam. — The  broken  ends  of  the  old  dam  reveal  a  poor 
quality  of  masonry  work  for  such  an  important  structure.  (See  Fig.  74,  page  131.) 
The  interior  of  the  dam  is  built  of  native  limestone,  poorly  laid  in  cement  mortar. 
The  joints  between  the  adjacent  stones  are  poorly  filled  and  it  is  evident  from  an  in- 
spection that  water  under  a  head  can  readily  penetrate  the  structure  to  almost  every 
part.  Holes  drilled  into  the  face  of  the  dam  during  reconstruction  permit  water  to 
seep  out,  and  it  was  still  slowly  running  from  these  holes  at  the  time  of  the  writer's 
inspection. 

The  grouting  logs  (see  log  of  holes  235,  236  and  261)  show  that  water  flowed 
readily  into  the  structure  and  its  foundations  when  holes  were  drilled  into  or  through 
the  apron,  and  that  during  grouting,  air  forced  into  these  holes  found  its  way  en- 
tirely under  the  dam  and  showed  above  the  dam.  (See  Mr.  Posey 's  evidence,  page 
93.) 

Stability  of  the  Old  Section  Under  Original  Conditions. — The  principles  of  safe 
dam  design  construction  were  not  so  well  understood  or  appreciated  in  1890  as  at 
present.  The  relations  between  the  weight  of  the  structure  and  the  pressure  of  the 
impounded  water,  and  the  danger  of  sliding  and  of  undercutting  at  the  toe,  were  un- 
derstood, but  the  danger  due  to  the  upward  pressure  of  water  under  the  dam,  trans- 
mitted through  cracks  and  fissures  in  the  foundation  rock,  was  often  disregarded. 
Uplift  can  sometimes  be  disregarded  with  safety  on  foundations  which  are  practically 
impervious  or  where  the  fractures  in  the  rock  are  few  and  small,  and  hence  the  area  on 
which  this  upward  pressure  is  exerted  is  of  limited  extent.  The  numerous  accidents 
which  have  occurred  to  dams  during  the  last  twenty-five  years,  have  emphasized  the 
necessity  of  taking  into  account  possible  upward  pressure,  and  of  designing  the  dam 
with  sufficient  section  to  withstand  the  pressure  which  is  likely  to  obtain.  It  has  also 
developed,  largely  through  the  experience  at  Austin,  that  when  large  quantities  of  silt 
will  be  deposited  behind  a  dam,  that  the  extra  pressure  against  the  structure  due  to 
this  silt  must  be  considered  in  the  design. 

In  the  original  section  of  the  Austin  dam,  the  height  of  the  crest  above  the  rock 
foundation  averaged  about  66  feet;  and  while  its  total  base  width  is  66  feet  (see 
Fig.  66,  page  125),  the  effective  width  for  the  purpose  of  conservative  estimating  and 
so  far  as  resistance  to  overturning  is  concerned,  is  only  about  42.75  feet,  for  it  is 
evident  that  the  long  slender  apron  of  the  dam,  built  of  poorly  laid  masonry  faced 
with  granite,  would  immediately  break  off  near  this  point  were  the  dam  actually  to 
overturn.  According  to  the  principles  previously  stated  (see  second  principle,  page 
115),  the  resultant  pressure  of  the  force  acting  on  the  dam  should  pass  through  the 
base  not  more  than  28.50  feet  from  the  upstream  face. 

It  is  evident  that  in  the  original  design,  the  presence  of  clay  seams  was  ignored, 
and  the  foundation  was  assumed  to  be  solid  limestone.  It  is  also  apparent  that  no 


Stability  of  Old  Dam. 


125 


allowance  was  made  in  the  design  for  silt  pressure  above  the  dam  or  for  upward  water 
pressure  from  underneath  the  dam,  for  it  is  found  that  with  water  at  the  spillway 
level,  and  with  no  water  below  the  dam,  the  resultant  pressure  passes  within  the  mid- 
dle third  (see  Fig.  66,  page  125).  The  resultant  R  makes  an  angle  of  63°45',  with  the 
base,  giving  the  value  of  .49  for  the  tangent  of  the  angle  of  friction ;  while  any  value 
below  .7  would  be  considered  safe  for  masonry  on  masonry  or  for  masonry  on  lime- 
stone rock  (see  third  principle,  page  115).  The  dam  would  therefore  be  considered 
safe  for  the  conditions  assumed. 


W.L.E/.  teo.o 


£/  99  O? 


Condi f ions  as  Probably  Original /y  flssvmed. 
Head  Wafer  £/eisafior>  •  J6O  O  Assumed 
Tai/  -  $4  O  » 

Si/f  -None 

Upward  Pressure  » 


FIGURE  66  —  Force  Diagram  of  Old  Dam  with  no  Tail 
Water  Upward  Pressure  or  Silt. 


Condi f/ofi  of  £o»  Wafer  about  Me  Year  /9OO 
Head  Wafer  £/evafion  -  /ffO.  O 
To//  "  -  99. 0 

5//f  "  /22  O 

We/gfif  af3'/tper  Cu.  ft.    -  //O.  O  * 

Upward  pressure  Assumed  at  r/ee/  of  Dam  -Ay//  Head. 
„  *  Toe  S  feet 

FIGUEE   67 — Force   Diagram   of   Old   Dam   with   Low 
Tail  Water  Full  Upward  Pressure  with  Silt  be- 
hind the  Dam. 


With  the  conditions  that  actually  exist  at  the  dam  site,  the  above  assumptions 
are  not  adequate  for  safety. 

In  the  first  place,  the  fractured  and  seamy  condition  of  the  foundation  and  the 
porous  nature  of  the  masonry  admit  the  water  pressure  into  and  under  the  structure 
of  the  old  dam.  For  safe  construction,  this  pressure  should  under  the  present  con- 
dition of  the  structure  be  assumed  equal  to  the  full  pressure  due  to  tlie  head  at  the 
upstream  face  of  the  dam,  and  may  be  considered  as  decreasing  to  zero  at  the  outer 
edge  of  the  toe  if  the  toe  is  properly  drained. 

In  the  second  place,  with  the  deposition  of  silt  against  the  dam,  as  shown  by  the 
investigations  of  Prof.  T.  U.  Taylor  (see  Fig.  19,  page  49),  it  is  evident  that  the 
pressure  due  to  this  deposit  must  be  considered. 


1 26  Report  on  the  Dam  at  Austin,  Texas. 

These  assumptions  produce  a  very  different  position  and  angle  of  the  resultant 
pressures  from  that  evidently  assumed  in  the  original  design  of  the  dam,  as  will  be 
noted  from  Fig.  67,  page  125.  This  diagram  shows  that  under  these  conditions 
the  resultant  pressure  falls  outside  of  the  middle  third  of  the  base,  and  while  this 
condition  does  not  necessarily  involve  failure,  it  indicates  an  undue  reduction  of  the 
factors  of  safety  and  a  departure  from  the  principles  of  present  good  practice. 

In  the  third  place,  the  rock  foundation  below  the  apron  and  on  the  east  half  of 
the  dam  was  in  such  a  cracked  and  fissured  condition  and  probably  so  interspersed 
with  clay  seams  that  it  was  rapidly  eroded  to  a  depth  below  the  plane  of  the  founda- 
tion of  the  dam,  and  the  toe  of  the  dam  was  undermined  by  the  currents  produced  by 
the  falling  waters.  In  this  manner,  the  toe  resistance  of  the  section  of  rock  and  other 
material  below  the  toe  of  the  dam  was  removed,  the  length  of  seepageway  from 
above  to  below  the  dam,  shortened,  and  the  security  of  the  dam  left  dependent  upon 
the  frictional  resistance,  which  was  quite  likely  reduced  by  the  seepage  which  had 
developed.  The  probable  coefficient  of  friction  under  these  conditions  was  reduced  to 
perhaps  .4  or  less,  while  the  tangent  of  the  angle  with  the  resultant  with  the  vertical 
was  1.01,  and  all  factors  were  therefore  favorable  for  disaster. 

During  the  flood  of  April,  1900,  the  conditions  shown  by  Fig.  68,  page  127  ob- 
tained. Under  these  conditions  the  resultant  passed  outside  of  the  effective  toe  of 
the  dam,  and  the  tangent  of  the  angle  of  friction  increased  to  1.23.  It  is  also  prob- 
able that  a  partial  vacuum  was  formed  on  the  lower  side  of  the  dam  under  the  sheet 
of  falling  water,  which  would  in  effect  add  to  the  head  above  the  dam;  and  under 
these  conditions,  failure  resulted. 

That  the  old  dam  was  stable  until  the  resistance  was  removed  from  below  its  toe, 
and  perhaps  until  some  considerable  seepage  had  developed  underneath  it,  is  shown 
by  the  fact  that  it  actually  stood  for  some  seven  years  (from  1893  to  1900).  The  fact 
that  its  failure  was  due  to  the  gradual  developments  of  weakness  in  the  foundation 
seems  established  by  the  fact  that  the  western  portion  of  the  dam,  where  the  ma- 
terial below  the  toe  was  more  resistant  and  was  not  removed  by  the  impact  and  en- 
ergy of  the  flood  waters  (see  soundings  on  pages  101  and  104)  still  stands,  although 
some  seepage  had  undoubtedly  developed  in  that  section  as  well.  It  is  nevertheless 
true  that  the  section  of  the  old  dam  even  with  the  rock  below  the  toe  intact,  has  too 
low  a  factor  of  safety  and  is  in  an  unsafe  condition. 

The  Use  of  the  Old  Section  for  the  Neiv  Conditions. — The  new  conditions,  under 
which  the  remaining  part  of  the  old  dam  constitutes  about  half  of  the  reconstructed 
dam,  are  described  by  Mr.  F.  S.  Taylor  in  the  Engineering  Eecord  of  May  24,  1915,  as 
follows : 

"In  order  to  get  the  proper  amount  of  power  and  lake  storage,  the  water 
level  would  have  to  be  raised  from  the  old  elevation  of  60  feet  to  65  feet  above 
low  water,  which  meant  that  with  11  feet  of  water  over  the  crest  during  flood, 
the  maximum  water  level  would  be  76  feet  above  the  low  water  instead  of  71 


Stability  of  Old  Dam. 


127 


feet.  The  portion  of  the  old  section  which  had  given  way  failed  under  a  71  foot 
water  level,  and  it  was  imperative  that  the  portion  of  the  old  section  remaining 
should  not  be  subjected  to  as  great  stress  as  it  had  previously  withstood.  This 
required  that  the  maximum  water  level  should  never  rise  even  as  high  as  71  feet 
above  low  water.  It  appeared  as  if  these  two  conditions  could  not  be  reconciled. 
However,  after  considerable  study,  a  type  of  crest  gates  *  *  *  was  adopted. 

"With  this  arrangement,  the  new  section  of  dam  was  built  only  51  feet  high 
from  low  water  to  crest,  or  9  feet  lower  than  the  old  section.     The  crest  gates 

WL£t\  mOf 

W.L&.  I6S.O 


66.O'- 


Cond/ttons  at  Time  of  /9OO  Fai/ure 
Head  Wafer  £/eraf/on  -  /?/  O 

To//         ••  - 


We/aht  of  Si/t  per  Ca  ft  -  //O.  O  # 

Upward  Pressure  assumed  of-  flee/  of  Oa/n  -  fo>/  rfead. 
Toa   »         '        24  f-ff* 

FIGUBE  68  —  Force  Diagram  for  Old  Dam  under 
the  Conditions  at  Time  of  Failure. 


Condition  of  iow  Wafer  tv/M  Gates, 
tieod  Water  £/er at/on   •  /65  O 
Tot/  ••  ••  99. 0 

SS/t  '  Worte 

Upward  Pressure  Assumed  at  Heef  of  Dam  -  /*///  Head 
•  Toe    -        •'  5  feet 


FIGURE    69 — Force   Diagram    for   Old   Dam   with 
Gates  under  Low  Water  Conditions. 


on  the  old  section  are  6  feet  high,  and  those  on  the  new  section,  15  feet,  so  that 

the  upper  edges  of  the  crest  gates  are  all  at  the  same  level,  66  feet  above  low  water. 

*  *  # 

"It  is  estimated  that  with  a  discharge  of  200,000  second  feet,  the  thickness 
of  the  water  over  the  crest  of  the  new  section  will  be  18  feet,  and  over  the  old 
section  9  feet.  This  means  that  the  present  dam  will  pass  50  per  cent,  more 
water  than  did  the  old  dam  when  it  failed,  but  the  elevation  of  the  water  in 
only  9  feet  above  the  crest  of  the  old  dam,  while  it  was  11  feet  above  the  crest 
when  the  weak  section  went  out  in  1900." 

Under  the  new  conditions  it  will  be  noted  that  five  feet  of  head  are  added  to  the 
water  behind  the  old  section  by  the  installation  of  crest  gates.     It  was  apparently 


128 


Report  on  the  Dam  at  Austin,  Texas. 


the  theory  of  the  design  that  silt  could  be  kept  away  from  the  back  of  the  dam  by 
the  use  of  sluice  gates.  It  is  the  opinion  of  the  writer  that  silt  cannot  be  drawn  from 
behind  the  old  section  by  the  flow  through  these  sluice  gates,  and  that  for  safety  a 
height  of  silt  even  greater  than  that  which  had  accumulated  above  the  old  dam  at 
the  time  of  its  destruction  should  be  assumed  behind  the  old  section.  The  old 
section  has  therefore  been  analyzed  for  the  following  conditions,  with  the  results 
shown : 

1.  For  no  Silt  and  Low  Water  Conditions  (see  Fig.  69,  page  127). — The  resultant 
passes  dangerously  near  the  toe  of  the  effective   section,  and  the  tangent  of  the 


W.I  £/.  /69. 0 


WL&  I65.O 


Conditions  of  Low  Wafer  with- Gates  ana  Probable  Maximum  SiM 
r/ead  Wafer  Elevafion   -  J65.O 
To/7  -  .  99.O 

Si  It  '  /45.0 

Weight  of  Sift  per  Ct/  ft  -  //O.  O* 

Upward  pressure  assumed  a/  rfee/  of  Pan?  -  Fu//  rfead. 
"  -  •          •      Toe    -        >•  5  r~eef. 


FIGURE    70 — Force   Diagram   for    Old   Dam   with 

Gates  under  Low  Water  Conditions  and  with 

Silt  behind  the  Structure. 


Conditions  of  Ord/narg  9' F/ood  over  •Spillway  with  Probable 
Maximum  3i/f. 

Head  Water  F/e ration  -   /69.O 

To//          "  H-         -  /2a<y 

Si/t  "         -  /45.O 

Weight  of  Si/ f  per  Cu.  ft    -  //O. 0  * 

Upward  pressure  asst/mea1  of  r/ee/  of  Perm  -  Fu//  Head. 
»  «  Toe     •        '        26  riser. 


FIGURE    71 — Force   Diagram    for   Old    Dam   with 

Nine    Foot    Flood    over    Spillway    and    with 

Probable  Maximum  Silt. 


angle  of  the  resultant  is  so  high  (1.09)  that  only  the  resistance  of  the  rough  bottom 
and  the  abutting  rock  below  the  toe  will  keep  it  from  sliding.  This  is  the  condition 
which  had  already  obtained  when  the  water  was  raised  to  elevation  165,  after  the 
new  dam  was  closed.  The  fact  that  it  did  not  fail  under  these  conditions  is  no 
evidence  that  it  was  not  close  to  disaster. 

2.  For  Silt  and  Low  Water  Conditions  (see  Fig.  70,  page  128). — This  analysis 
shows  that  under  these  assumptions  the  resultant  pressure  passes  outside  of  the  ef- 


Stability  of  Old  Dam. 


129 


fective  toe,  and  the  dam  would  probably  crack  the  masonry  of  the  apron  and  tip 
over.  The  deposition  of  silt  would  therefore  create  an  extremely  hazardous  condi- 
tion, probably  resulting  in  failure. 

3.  For  Silt  With  a  Nine  Foot  Flood  (see  Fig.  71,  page  128). — This  analysis  is 
made  on  the  basis  of  a  flood  of  nine  feet  over  the  old  dam,  as  outlined  by  Mr.  Taylor 
in  the  above  quotation.  Silt  pressure  is  also  assumed  with  the  silt  surface  15  feet 
below  the  old  crest  of  the  dam.  This  condition  is  still  more  hazardous  than  that 
shown  in  case  2. 


W.L.&.  I74..p~y 


Conditions  of  Probab/e  Max/mc/m  f/ood. 
Head  Wafer  &avat/on    -  /74.O. 
Tart  .  ••  J40.O. 

Silf  ••  S/one. 

Upward  Pressure  assumed  of  /lee/  of  Dam  -  fV//  Head. 
••     Toe   .        „ 


FIGUKE  72  —  Force  Diagram  for  Old  Dam  under  Probable  Maximum  Flood   Conditions 

and  with  no  Silt. 

4.  For  a  Maximum  Flood  Without  Silt.  —  It  is  generally  conceded  that  a  max- 
imum flood  may  occur  which  would  flow  23  feet  deep  over  the  crest  of  the  new 
section  and  14  feet  over  the  crest  of  the  old  section  (see  Fig.  72,  page  129).  Even 
without  any  extra  pressure  due  to  silt,  this  condition  would  be  dangerous  as  the  re- 
sultant pressure  would  pass  through  the  effective  toe.  With  silt  behind  the  dam,  the 
resultant  pressure  would  pass  beyond  the  effective  toe  of  the  dam  and  apparently 
assure  failure. 

In  some  of  the  above  cases,  in  which  the  resultant  pressure  passes  outside  of  the 
middle  third  of  the  base  width  of  the  dam,  analyses  will  show  that  the  resultant  pres- 
sures for  horizontal  divisions  of  the  dam  above  the  base  will  also  pass  outside  of  the 


130  Report  on  the  Dam  at  Austin,  Texas. 

middle  third  of  the  base  line  of  such  divisions.  It  is  almost  as  essential  to  correct 
the  section  of  the  dam  for  these  conditions  as  for  the  same  conditions  of  the  base. 
The  actual  tensile  and  shearing  strength  of  the  masonry,  which  is  ordinarily  not  con- 
sidered in  the  calculations  for  such  structures,  may  however  be  relied  upon  to  de- 
velop practically  a  greater  strength  than  will  exist  between  the  masonry  and  the  un- 
derlying rock. 

The  assumptions  made  in  these  analyses  are  in  no  sense  extreme  and  are  no 
greater  than  good  practice  requires  or  than  the  writer  would  assume  were  he  con- 
sidering the  dam  for  his  own  use. 

The  Reinforced  Concrete  Structure. — It  has  already  been  noted  (see  page  67) 
that  the  width  of  the  new  dam  as  originally  specified  was  reduced  from  125'9"  to  93' 
on  the  detailed  plans  submitted  in  May,  1912,  and  approved  by  Dr.  Scott,  without 
the  knowledge  of  the  City  Council  of  the  reduction  made.  It  is  apparent,  however, 
that  under  the  terms  of  the  contract,  such  knowledge  or  consent  of  the  City  Council 
was  not  necessary,  provided  the  stability  of  the  structure  was  not  impaired.  The 
reasons  for  reducing  the  width  of  the  dam  are  set  forth  by  Mr.  F.  S.  Taylor,  in  the 
Engineering  Record  of  May  29,  1915,  as  follows: 

"Owing  to  the  difficult  character  of  the  foundation,  *  *  *  it  was  desirable 
to  make  the  distance  through  the  bottom  of  the  dam,  measured  from  upstream  to 
downstream  side,  as  short  as  possible.  In  the  usual  form  of  design  the  inclined 
deck  goes  up  to  the  elevation  of  the  crest  of  the  dam,  where  it  joins  with  the 
spillway.  The  form  of  the  spillway  is  determined  by  the  application  of  the  or- 
dinary parabolic  formula,  and  this  gives  a  certain  distance,  measured  horizon- 
tally, from  the  crest  of  the  spillway  down  to  its  toe.  As  shown  in  the  typical  sec- 
tion, the  spillway  was  designed  in  accordance  with  the  usual  method,  and  the 
sloping  deck  made  to  intersect  it  at  some  25  feet  farther  downstream  and  6  feet 
lower  vertically  than  in  the  customary  design.  By  this  method  a  proper  length 
of  theoretically  designed  spillway  was  made  available,  as  well  as  an  inclined  deck 
of  substantially  the  total  height  up  to  the  spillway,  and,  at  the  same  time,  the 
length  through  the  dam  from  front  to  back  was  reduced  about  25  feet,  diminish- 
ing in  like  proportion  the  length  of  the  transverse  walls,  the  length  of  each  trans- 
verse wall  foundation,  and  eliminating  one  longitudinal  wall.  While  the  saving 
in  material  and  labor,  due  to  this  form  of  design,  for  a  given  factor  of  safety, 
was  greatly  reduced  by  the  adoption  of  this  design,  the  cost  of  the  form  work  was 
increased  so  that  the  net  saving  effected,  though  considerable,  was  not  so  great 
as  would  at  first  appear." 

Foundation  Pressures. — The  foundation  pressures  under  the  new  structure  are 
regarded  as  dangerous  with  the  exposed  condition  of  the  strata  below  the  toe  of  the 
dam,  but  entirely  safe  if  the  foundation  rock  is  rendered  stable  by  proper  protection 
below  the  toe.  The  writer  is  unable  to  understand  why  the  difficulties  of  the  foun- 


Seepage. 


FIGUBE   73 — Pervious   Strata  at  Entrance  to   Walsh's   Slough. 


FIGURE  74 — Broken  Section  of  Original  Dam  Showing  Pervious  Nature  of  Masonry. 


^^"''•j  i     i    «  ' 

•  Report   on   the  Dam   at   Austin,   Texas. 


FIGURE  75 — Arrangement  of  Foundation  Walls  and  Sluiceways  of  New  Dam. 


FIGURE  7G — Foundation  Rock  for  Mats  in  Front  of  Sluiceways. 


Reinforced  Concrete  Dam.  1 33 

dation  made  it  desirable  to  narrow  the  width  of  the  dam  section  (as  stated  by  Mr. 
Taylor  in  the  above  quotation).  The  cheapening  of  the  cost  of  construction  is  a  more 
obvious  explanation. 

The  weight  of  the  dam  and  the  water  pressure  on  the  upstream  deck  were  re- 
duced somewhat  by  the  change  in  design ;  and  the  resultant  pressure,  due  to  the  com- 
bined forces  acting  on  the  dam,  intersects  the  horizontal  at  a  less  angle  in  the  new 
section  than  in  the  original  design  (see  Fig.  6,  page  18),  thereby  increasing  slightly 
its  tendency  to  slide  on  the  foundation,  or  for  the  foundation  to  slide  on  the  clay 
seams  which  are  known  to  exist  beneath  the  structure.  However,  the  effect  of  this 
change  is  regarded  as  of  little  consequence  so  far  as  the  stability  of  the  structure  is 
concerned,  and  if  the  dam  constructed  on  the  original  lines  could  be  considered  safe 
under  the  other  conditions  of  construction,  the  new  design  would  be  considered 
practically  as  safe.  The  change  in  the  width  of  the  dam  is  considered  as  quite  in- 
significant as  compared  with  other  and  more  serious  defects  in  the  design  and  con- 
struction of  the  dam. 

The  clay  seams  under  the  foundation  and  the  trench  in  the  rock  below  the  toe 
create  a  real  danger  of  sliding,  and  the  writer  regards  either  the  old  or  the  new  de- 
sign as  unsafe  under  the  foundation  conditions  as  they  now  exist. 

Hollow  Dam  Section. — As  already  noted  (principle  6,  page  116),  the  foundation 
of  a  dam  must  be  practically  impervious,  or  the  dam  must  be  so  designed  that  any 
seepage  water  will  be  forced  to  travel  such  a  distance  that  its  erosive  power  will  be 
consumed  in  friction  before  it  discharges  below  the  dam. 

The  advantages  of  a  hollow  dam,  in  obviating  upward  pressure  on  the  dam  base, 
as  stated  by  Mr.  Taylor  (see  page  117),  are  largely  imaginary.  If  the  foundation  is 
pervious,  and  its  upper  four  or  six  feet  are  by  construction  rendered  tight;  the  up- 
ward pressure  will  be  exerted  on  the  foundation  rock  so  tightened.  If  the  founda- 
tion is  pervious,  the  cutoff  wall  (in  this  case  about  30  inches  wide)  is  all  that  divides 
the  tail  water  from  the  head  water,  and  the  line  of  friction  resistance  is  too  short. 

If  the  new  section  had  been  made  solid,  it  is  probable  that  it  would  not  be  leak- 
ing at  this  time,  and  although  it  might  be  subject  to  upward  pressure  at  the  point 
where  the  leak  has  now  developed,  and  possibly  at  many  other  points,  it  would  still 
be  safe  if  designed  for  such  conditions,  and  it  would  have  afforded  a  resistance  to 
the  travel  of  seepage  water  70  or  more  feet  in  width  instead  of  30  inches. 

Design  of  Reinforced  Concrete  in  the  Reinforced  Concrete  Dam  Section. — A  typi- 
cal section  of  the  new  reinforced  concrete  dam  is  shown  by  Fig.  6,  page  18.  Two 
views  showing  the  arrangement  of  the  foundation  walls,  sluiceway  arched  roofs  and 
the  sluiceway  protecting  mats  during  construction  are  shown  in  Figs.  75  and  76,  page 
132.  The  following  is  taken  from  the  article  by  Frank  S.  Taylor  in  the  Engineering 
News  of  June  3, 1915,  and  indicates  the  basis  of  design : 

"As  indicated,  it  (the  new  dam  section)  is  a  reinfo reed-concrete  structure, 
having  an  inclined  upstream  wall,  making  an  angle  of  42°  to  the  horizontal.    At 


1 34  Report  on  the  Dam  at  Austin,  Texas. 

a  point  about  2y2  feet  above  low  water  level,  this  slope  of  the  wall  ends,  inter- 
secting a  narrow  horizontal  bench,  and  from  the  upstream  edge  of  this  bench  a 
vertical  wall  goes  straight  down  into  the  rock  and  forms  both  the  lower  por- 
tion of  the  deck  and  the  cutoff  wall. 

"The  object  of  the  bench  is  to  allow  flow  of  water  through  any  completed 
section  of  the  dam  during  construction,  the  flat  horizontal  slab,  which  runs  the 
entire  length  of  the  dam  and  covers  the  upper  part  of  the  bench,  being  omitted 
until  the  completion  of  the  work.  Normally,  during  construction  the  total  flow 
of  the  river  was  taken  through  the  sluice  gates  in  the  bottom  of  the  dam,  but 
during  floods  the  openings  through  the  horizontal  bench,  together  with  the  area 
afforded  by  the  sluice  gates,  would  usually  take  care  of  the  whole  river  flow, 
with  an  elevation  in  the  water  level  of  not  more  than  4  to  6  ft. 

"The  supporting  walls  are  both  longitudinal  and  transverse.  The  latter 
are  parallel  to  the  flow  of  the  stream  and  are  20  feet  apart.  The  longitudinal 
walls  are  also  20  feet  apart,  measured  from  center  to  center  in  a  direction  at 
right  angles  to  them,  and  are  inclined  at  an  angle  of  nearly  90°  with  the  up- 
stream deck.  Their  slope  is  such  that  the  resultant  of  the  forces  which  they  re- 
sist, made  up  of  the  water  pressure  acting  against  the  surface  of  the  deck  and 
the  gravity  component  of  the  deck  and  the  walls  themselves,  has  the  same  direc- 
tion as  that  of  the  longitudinal  walls.  The  longitudinal  and  transverse  support- 
ing walls  intersect  at  right  angles  and  form  a  series  of  square  openings  when 
viewed  in  a  direction  normal  to  the  deck  in  which  the  reinforcing  steel  is  placed 
both  longitudinally  across  the  length  of  the  dam  and  transversely  up  and  down 
the  deck,  the  bars  being  laid  closer  and  closer  together  as  they  get  nearer  and 
nearer  to  the  middle  of  each  panel. 

"All  of  the  steel  used  was  rerolled  twisted  bars  having  an  elastic  limit 
above  55,000  Ibs.  The  stresses  allowed  in  the  steel  were  16,500  Ibs.  per  sq.  in. 
maximum. 

"An  ample  number  of  expansion  joints  is  provided  in  the  new  concrete  dam, 
every  fifth  panel  being  an  expansion  panel.  There  are  28  panels  in  all.  The  ex- 
pansion panels  have  both  the  upstream  deck  and  the  spillway  entirely  separated 
from  the  adjacent  portions  of  deck  and  spillway  on  either  side  of  it.  A  joint  is 
made  between  the  two  abutting  edges  of  the  concrete  slabs,  which  is  water- 
tight, but  which  permits  lateral  movement  of  the  different  sections  of  the  dam 
without  diminishing  the  tightness  of  the  joint  or  rupturing  any  of  the  masonry. 
This  joint  is  made  of  'ingot-iron'  plate,  y2  x  8  inches.  One-half  the  width  of  the 
strip  is  cast  into  the  concrete  of  the  abutting  edge  of  a  standard  panel.  This 
leaves  4  in.  of  metal  projecting  out  from  the  surface  of  the  end  of  the  panel. 
The  end  of  the  slab,  together  with  the  projecting  iron,  is  painted  with  a  heavy 
coat  of  asphalt.  The  expansion  panel  is  then  cast  so  that  its  edge  abuts  against 
the  edge  of  the  slab  of  the  standard  panel.  Since  its  construction  the  dam  has 


Reinforced  Concrete  Dam.  1  35 

been  subjected  to  temperatures  varying  from  32  to  90°.  and  these  expansion 
joints  have  proved  thoroughly  satisfactory.  Before  construction  was  quite 
completed  and  when  the  whole  of  the  dam  was  still  exposed  to  the  sun  and  at- 
mospheric conditions,  it  was  possible  to  see  the  space  between  the  abutting  ends 
of  the  panels  at  expansion  joints  change  more  than  14  inch  in  a  few  hours. ' ' 

From  an  examination  of  the  detailed  drawings  (C-9  to  C-17),  it  does  not  appear 
that  the  expansion  joints  were  uniformly  placed,  one  for  each  five  panels,  but  that 
a  spacing  of  one  in  five,  six  and  seven  panels  respectively  was  used. 

The  drawings  further  indicate  that  all  of  the  steel  reinforcement  in  the  up- 
stream deck  consists  of  %"  square  bars.  The  bars  near  the  upper  side  of  the  slab 
for  the  bottom,  middle  and  top  inclined  decks  were  spaced  about  13-inch  centers  at 
the  center  of  the  slab,  the  spacing  of  the  rods  increasing  toward  the  supports.  The 
rods  near  the  lower  side  of  the  slab  are  spaced  at  7,  7y2  and  8  inch  centers  respec- 
tively for  the  bottom,  middle  and  top  decks;  the  spacing  applying  to  the  center  of 
the  slab  and  uniformly  increasing  toward  the  supports.  The  slabs  were  reinforced 
essentially  equally  in  both  directions. 

In  estimating  the  stress  to  which  the  steel  is  subjected  as  per  size  and  spacing 
shown  on  the  detailed  drawings,  the  loads  on  the  slabs  for  the  bottom  deck  have 
been  calculated  with  the  water  level  at  elevation  165.  For  the  loads  on  the  middle 
and  the  top  decks,  the  head  water  has  been  taken  at  elevation  174  and  the  tail  water 
at  elevation  128.  The  conditions  above  will  give  the  maximum  loading  for  the  slabs 
in  each  of  the  three  decks.  Any  extra  loading  on  the  deck  on  account  of  silt  has  not 
been  considered,  but  it  has  been  assumed  that  any  accumulation  of  silt  immediately 
above  and  adjacent  to  the  reinforced  structure  can  be  removed  through  the  sluice 
gates. 

In  the  analysis  of  the  stresses  to  which  the  steel  will  be  subjected  due  to  the 
loading,  the  recommendations  laid  down  by  the  Joint  Committee  on  Reinforced  Con- 
crete have  been  followed :  That  is,  in  the  case  of  continuous  beams  supported  on  45° 
brackets,  the  end  of  the  beam  may  be  taken  to  be  that  point  where  the  depth  of  beam 
and  bracket  equals  one-third  more  than  that  of  the  beam.  In  the  case  under  con- 
sideration, viz :  the  slab  forming  the  upstream  deck  of  the  dam,  the  span  length  is 
taken  at  15  feet  4  inches.  The  actual  distribution  of  the  bending  moment  and  there- 
fore of  the  stress  is  uncertain,  and  not  capable  of  rigid  mathematical  analysis.  On 
the  basis  of  the  most  logical  assumptions,  it  is  believed  that  the  stress  in  the  steel 
over  the  supports  may  equal  but  would  not  exceed  23,000  pounds  per  square  inch. 
At  the  center  of  the  slab,  the  stress  would  not  exceed  19,000  pounds  per  square  inch. 
Considering  the  character  of  reinforcing  steel  used,  and  the  form  of  the  slabs, 
it  is  believed  that  the  structure  is  safe  so  far  as  the  strength  of  the  reinforced  con- 
crete is  concerned,  although  the  stresses  are  somewhat  higher  than  is  said  to  have 
been  used  as  a  basis  of  design,  and  somewhat  higher  than  the  writer  would  consider 
as  good  practice. 


1 36  Report  on  the  Dam  at  Austin,  Texas. 

Appurtenances. — The  appurtenances  furnished  with  the  reconstruction  are  in 
general  of  the  cheapest  class  that  could  be  utilized  for  each  specific  purpose. 

Sluice  Gates. — The  original  design  for  the  sluice  gates  showed  that  the  hydrau- 
lic cylinders  by  which  the  gates  can  be  operated  were  to  be  placed  on  the  inside  of 
the  dam  where  they  would  be  accessible  for  adjustment,  maintenance  and  repair. 
(See  A  Fig.  7,  page  72).  The  cylinders  were,  however,  actually  placed  on  the  up- 
stream face  of  the  dam.  (See  B  Fig.  7,  page  22  and  Fig.  77,  page  137.)  Mr.  F.  S. 
Taylor,  in  his  article  in  the  Engineering  Record,  previously  referred  to,  comments  on 
this  change  in  plans  as  follows : 

"It  is  to  be  noted  that  the  cylinders  are  placed  on  the  deck  of  the  dam  instead 
of  inside,  as  is  customary.  In  this  way  the  cylinders  could  be  placed  much 
nearer  the  sluice  gates  than  if  they  were  inside  the  dam,  and  the  sluice  gates  out- 
side. This  shortens  the  piston  rod,  and  thus  a  smaller  rod  may  be  used.  This 
means  that  the  size  of  the  cylinders  may  be  somewhat  reduced.  Furthermore, 
the  saving  in  concrete  and  form  work  amounted  to  some  $5,000.  Moreover,  not 
having  any  inset  made  in  it,  the  dam  is  stronger  than  it  would  otherwise  be. 

"This  method  of  installation  has  the  apparent  objection  that  the  cylinders 
cannot  be  inspected  or  repaired,  as  they  are  normally  under  60  feet  of  water. 
This  objection,  the  designers  feel,  is  an  academic  one.  The  extent  of  opera- 
tion of  these  gates  will  never  be  sufficient,  in  many  years,  for  the  element  of  wear 
to  have  any  bearing  on  the  subject.  An  ordinary  Corliss  engine,  in  two  hours, 
will  make  more  strokes  than  these  cylinders  will  in  fifty  years.  Metallic  pack- 
ing is  provided  so  that  it  is  permanent  and  not  subject  to  deterioration  with  time, 
as  most  organic  substances  would  be.  The  pistons  are  of  bronze,  so  that  there 
is  not  the  least  danger  of  them  sticking  or  rusting  to  the  interior  of  the  cylin- 
ders, and  this  is  further  prevented  by  the  cylinders  being  constantly  filled  with 
oil." 

The  cylinders  in  these  gates  are  so  small  that  they  have  to  be  operated  under 
very  heavy  pressures,  and  the  probability  that  they  will  need  occasional  attention  is 
quite  obvious.  After  the  plant  is  placed  in  operation,  the  emptying  of  the  reservoir 
(which  must  necessarily  be  done  under  low  water  conditions)  will  involve  in  each 
instance  a  power  loss  equal  to  that  which  could  be  generated  by  the  water  it  will  take 
to  fill  it.  This  is  estimated  as  equal  to  about  2,000,000,000  cubic  feet  with  65-foot 
head,  and  to  about  1,300,000,000  cubic  feet  with  a  60-foot  head.  If  power  is  valued 
at  .9c  per  horse  power  hour,  the  loss  caused  by  the  emptying  of  the  reservoir  would 
be  approximately  $21,000  with  the  65-foot  head  and  $14,000  with  the  60-foot  head, 
for  each  time  the  reservoir  is  emptied  to  repair  the  gates  or  hydraulic  cylinders.  This 
can  hardly  be  called  an  academic  question,  and  the  saving  of  $5,000  to  the  City 
Water  Power  Company  at  such  an  ultimate  inconvenience  and  expense  in  the  opera- 
tion of  the  plant,  is  a  short  sighted  policy  which  should  not  have  been  adopted. 


Appurtenances. 


137 


FIGURE  77 — Sluice  Gates  and  Cylinders  on  Deck  of  Dam,  Gates  raised. 


FIGURE  78— Accumulation  of  Drift  above  the  Dam  during  Flood  of  September,  1915. 


138 


Report  on  the  Dam  at  Austin,  Texas. 


FIGURE  79 — Accumulation  of  Drift  above  the  Dam  during  Flood  of  September,  1915. 


FIGUEE  80 — Drift  obstructing  Gateways  during  Flood  of  September,  1915. 


Appurtenances.  1 39 

The  design  of  the  gate  itself  is  quite  as  defective  as  the  arrangement  of  the  hy- 
draulic cylinders.  The  bronze  strips  attached  to  the  face  of  the  gates  and  to  the  gate 
frames,  are  %  inch  in  thickness  and  are  designed  to  be  held  in  place  by  countersunk 
screws.  These  strips  are  so  light  and  narow  that  they  cannot  be  held  in  place  under 
the  heavy  friction  of  operation,  and  are  now  in  such  bad  condition  that  some  of  the 
gates  are  leaking  badly. 

No  racks  or  other  protection  has  been  provided  for  these  gates,  and  water-log- 
ged drift  has  been  and  will  be  drawn  into  them,  preventing  their  closing  and  their  ef- 
ficient operation, 

Crest  Gates. — It  is  unnecessary  to  comment  at  length  on  the  crest  gates,  as  they 
have  already  demonstrated  their  inadequacy  for  the  conditions  at  the  dam.  The 
gates  are  of  a  light  flimsy  construction  and  of  entirely  inadequate  design  for  a  drift 
bearing  stream.  The  swelling  of  forms  and  the  rough  concrete  work  on  the  gate 
piers  render  it  impossible  to  secure  tightness  and  free  action,  both  of  which  are  es- 
sential for  such  gates. 

The  gates,  swinging  in  the  current,  offer  a  material  obstruction  to  the  flood  flow 
and  especially  to  the  heavy  drift  which  is  borne  by  the  Colorado.  (See  Figs.  78,  79  and 
80,  pages  137  and  138.) 

Tail  Race. — The  specifications  for  the  tail  race  are  quoted  in  paragraphs  30  and 
31  on  pages  64.  These  requirements  have  not  been  carried  out.  Apparently 
the  discharge  from  the  draft  tubes  is  throttled  by  a  face  of  rock  close  in  front  of  them. 
The  temporary  raceway  provided  is  practically  filled  at  various  points  between  the 
power  house  and  the  river,  and  every  flood  will  add  to  the  obstruction  from  the 
pile  of  debris  which  lies  just  north  of  the  raceway.  (See  Figs.  8  and  9,  page  25.) 

Passageway  in  Dam. — A  plank  walk,  supported  on  wooden  joists,  is  provided 
through  the  dam  in  the  interior  of  the  reinforced  concrete  structure.  The  decay, 
caused  by  the  saturated  air  in  the  dam,  has  already  weakened  the  structure  so  that  it 
sags  badly,  and  this  walk  will  have  to  be  replaced  for  safety  within  a  very  brief 
period.  A  gas  pipe  railing  is  provided  along  each  side  of  this  walk.  This  railing  has 
never  been  painted  and  is  rapidly  corroding ;  it  will  soon  be  destroyed  unless  some 
attention  is  given  to  its  preservation. 

Railing  on  Dam. — The  railing  along  the  platform  on  top  of  the  dam  is  incom- 
plete. No  railing  had  been  provided  or  apparently  planned  from  the  top  of  the  dam 
along  the  retaining  wall  to  the  building.  This  location  is  one  which  sightseers  are 
apt  to  visit  in  order  to  view  the  structure,  and  its  unprotected  condition  is  a  source 
of  danger.  (See  Figs.  9  and  46,  pages  26  and  99.) 

Head  Gate  Masonry. — The  masonry  of  the  head  gate  is  said  by  Mr.  Posey  to  leak 
considerably  whenever  the  reservoir  is  filled.  As  the  writer  has  not  personally  had 
an  opportunity  to  observe  this  condition,  he  is  unable  to  say  how  serious  this 
matter  may  become. 


140  Report  on  the  Dam   at  Austin,  Texas. 

Head  Gate  Racks. — The  original  racks  installed  in  front  of  the  head  gates  are 
shown  on  Construction  Drawing  F-31.  They  were  built  of  bars  14"  thick,  spaced 
1%"  apart.  They  were  about  10  feet  in  length  and  their  curved  tops,  which  reached 
about  one  foot  above  the  penstock  entrance,  were  so  arranged  as  to  leave  an  open- 
ing about  5"  wide  and  10  feet  long  in  front  of  each  penstock.  As  the  racks  were 
deeply  submerged,  drift  readily  entered  the  penstocks  from  over  the  racks  and 
caused  considerable  breakage  of  the  turbine  gates  during  their  brief  operation.  The 
Engineers  of  the  City  insisted  on  a  change  in  the  design  of  the  racks,  and  the  new 
racks  were  built  with  their  tops  well  above  ordinary  water  level,  and  with  a  free 
opening  between  the  14"  bars  of  only  %".  This  arrangement,  while  preventing  an 
inflow  of  drift,  screens  even  the  finer  material  from  the  water  and  throttles  the  inflow 
to  the  turbines. 

Head  Gate  Hoists. — The  head  gate  hoists  (see  Fig.  81,  page  141)  installed  on  this 
work,  are  of  a  cheap  type  which  are  seldom  used  except  on  small  country  mill  head 
gates.  On  any  first  class  plant  the  head  gate  hoists  should  be  of  such  design  that  the 
gates  may  be  moved  rapidly  and  easily  into  position,  and  the  best  practice  would 
warrant  the  use  of  a  hoist  electrically  as  well  as  hand  operated. 

Penstocks  and  Draft  Tubes. — The  penstocks  and  draft  tubes  have  been  con- 
structed mainly  from  the  old  material  used  in  the  original  (1890-93)  construction 
(see  Fig.  14,  page  43).  The  various  elbows  and  bonds  are  of  new  material.  The  pen- 
stocks outside  of  the  power  house  have  been  reinforced  with  concrete  and  are  ap- 
parently in  fair  condition,  although  no  examination  was  possible  under  service.  The 
draft  tubes  are  placed  in  such  an  exposed  position  that  they  are  liable  to  injury  from 
floating  drift  during  every  flood  (see  Figs.  8  and  9,  page  25).  They  are  said  to 
have  leaked  air  so  badly  at  the  time  the  turbines  were  tested  that  they  were  re- 
calked,  and  finally  rendered  fairly  tight  with  Portland  cement.  The  north  draft 
tube  has  been  twisted  somewhat  out  of  place,  apparently  by  drift. 

Station  Equipment. — The  station  equipment  was  not  examined  in  great  detail, 
and  no  conditions  in  the  station  were  noted  where  serious  criticism  is  warranted. 
The  machinery  appears  to  be  in  fairly  good  condition.  No  definite  statement  can 
be  made  concerning  its  character  without  a  more  detailed  examination  under  oper- 
ating conditions.  The  machinery  has  been  standing  idle  for  almost  two  years  and 
has  undoubtedly  depreciated  to  an  extent  quite  equal  to  two  years  of  active  opera- 
tion. 

Transmission  Line. — The  wooden  pole  line,  as  far  as  examined,  seemed  to  be  in 
fairly  satisfactory  condition ;  but  the  wooden  strain  towers  built  to  take  the  stress  of 
the  outgoing  lines  adjacent  to  the  station  (see  Figs.  82  and  83,  pages  141  and  142) 
are  an  objectionable  and  unworkmanlike  construction  which  should  not  have  been  per- 
mitted. 

Pumps. — The  centrifugal  pumps  furnished  under  the  contract  were  found  to  have 
a  capacity  of  about  4,000,000  gallons ;  and  in  order  to  fulfill  the  contract,  a  third  pump 
of  similar  capacity  was,  by  agreement  with  the  City  Council,  furnished  by  the  con- 


Appurtenances. 


141 


FIGUKE  81 — Headgate  Hoists. 


.  • 


FIGURE  82 — Power  House  showing  objectionable  appearance   of   Strain   Tower   of  Transmission   Line. 


142 


Report  on  the  Dam  at  Austin,   Texas. 


FIGURE  83 — Wooden  Strain  Tower  at  Power  House  Entrance. 


Reservoir.  1 43 

tractor.  Two  of  these  pumps  have  been  erected  in  the  main  pumping  station,  while 
the  third  one  was  erected  in  the  north  pumping  station.  This  pump  was  connected  to 
the  discharge  main  by  a  line  of  flange  pipe  and  fittings  30  feet  or  more  in  length. 
This  connection,  the  writer  was  advised,  was  when  erected  some  6  or  8  inches  out  of 
line  but  was  strained  into  position  and  the  bolts  duly  tightened.  Since  its  connec- 
tion, due  to  the  initial  strains  caused  by  this  lack  of  alignment,  and  perhaps  by  the 
shock  and  jar  due  to  the  operation  of  the  plant,  this  pipe  has  broken  down,  breaking 
the  discharge  flange  from  the  pump  and  making  it  necessary  to  send  this  unit  to  the 
shops  for  repair. 

The  writer  also  examined  one  of  the  pumps  which  had  been  dismantled,  in  the 
main  pumping  station,  and  found  that  it  is  so  badly  cut  by  the  sand  drawn  up  with 
the  water  supply  as  to  render  it  practically  useless  without  material  repair. 

The  bearings  on  all  of  these  pumps  are  said  to  heat  badly  during  operation. 

Reservoir. — The  ten-million  gallon  reinforced  concrete  reservoir,  furnished  un- 
der the  contract,  has  now  been  in  service  for  several  years  and  has  apparently  given 
satisfaction.  It  seems  well  built  but  is  of  exceedingly  light  construction.  It  can 
probably  be  maintained  without  any  undue  expense.  This  reservoir  is  uncovered, 
and  the  waters  are  exposed  to  dust  and  sunlight.  These  conditions  will  give  rise  to 
algae  growth  in  the  impounded  waters  and  will  cause  an  unsatisfactory  condition  of 
the  water  during  the  summer  months,  which  can  be  remedied  only  by  emptying  the 
reservoir  and  carefully  cleaning  it  as  often  as  the  condition  becomes  sufficiently  un- 
satisfactory, unless  a  roof  is  provided  to  shut  out  the  dust  and  sunlight. 


APPENDIX  6 

A  STUDY  OF  THE  STREAM  FLOW  OF  THE  COLORADO  RIVER  AND  THE  PROBABLE  AMOUNT  OF 
POWER  THAT  CAN  BE  DEVELOPED  AT  THE  AUSTIN  DAM  WITH  A  COMPARISON  OF  THE 
RELATIVE  VALUES  OF  65  AND  60  FOOT  HEADS 


The  amount  of  power  that  can  be  developed  under  various  conditions  of  head 
and  flow  is  an  important  element  in  the  problem  of  the  rehabilitation  of  this  plant. 
It  is  therefore  essential  to  examine  this  matter  in  considerable  detail. 

Stream  Flow  Data. — The  flow  of  the  Colorado  is  of  primary  importance  in 
power  development  at  this  plant,  and  much  study  has  been  given  to  its  determina- 
tion. The  U.  S.  Geological  Survey  began  to  make  stream  flow  observations  on  the 
Colorado  at  Austin  in  1896,  but  accurate  detailed  data  covering  the  period  before 
February,  1898  have  not  been  obtained.  For  the  years  1912  and  1913,  no  observa- 
tions were  made  by  the  Geological  Survey,  but  gage  readings  by  the  U.  S.  Weather 
Bureau  are  available. 

The  sources  of  stream  flow  data  used  in  this  report  are  as  follows : 

No.  of  Water  Supply  For 

Paper  TJ.  S.  G.  S.  Page  Year 

28  124  1898 

37  274  1899 

50  337  1900 

66  64  1901 

84  151  1902 

99  335  1903 

132  38  1904 

174  25  1905 

210  38  1906 

288  29  1907 

288  29  1908 

288  30  1909 

288  30  1910 

308  16  1911 


Stream  Flow  Data.  145 


No.  of  Water  Supply  For 

Paper  U.  S.  G.  S.  Page  Year 

•Weather  Bureau  1912 

Weather  Bureau  1913 

Weather  Bureau  1914  (Jan.  1— Sept.  30) 

408  18  1914  (Oct.  1— Dec.  31) 

408  18  1915  (Jan.  1— Sept.  30) 

438  30  1915  (Oct.  1— Dec.  31) 

438  30  1916  (Jan.  1— Sept.  30) 

**Blue  Print  1916  (Sept.  30— Dec.  31) 

Blue  Print  1917  (Jan.  1— July  19) 

While  the  flow  of  the  stream  for  most  of  the  years  considered  has  been  calcu- 
lated and  published  in  the  Water  Supply  Papers  named  above,  it  was  considered  de- 
sirable to  check  the  computations  in  the  light  of  the  later  flow  data  which  are  now 
available.  A  general  view  of  the  entire  series  of  observations  has  led  to  the  con- 
clusion that  some  of  the  published  calculations  are  somewhat  in  error,  and  many  of 
the  earlier  discharges  have  been  recalculated  in  order  to  give  a  more  accurate  basis 
for  power  calculations.  These  recalculations  in  detail,  together  with  a  discussion  of 
the  basis  on  which  they  have  been  made,  with  the  rating  curves  used  in  the  computa- 
tions, have  been  furnished  to  the  City  of  Austin  in  manuscript  form. 

In  general,  these  calculations  have  reduced  those  given  in  the  published  tables, 
especially  for  mean  and  minimum  flow  conditions,  as  will  be  noted  from  the  follow- 
ing comparisons: 

COMPARISON  OF   PUBLISHED   RECORDS  AND  THOSE  COMPUTED  FOR  AUSTIN  DAM 

Maximum  Minimum  Yearly  Mean 

Year  Published  Report  Published        Report  Published  Report 

1902   31,250  34,200  180  178  2,224  2,290 

1903   33,070  33,100  320  336  2,157  2,120 

1904   46,140  29,300  200  147  1,595  1,470 

1905   51,190  48,100  175  175  1,918  1,880 

1906   70,300  64,400  175  153  3,060  2,950 


*From  "Gauge  Heights"  Published  by  the  U.  S.  Weather  Bureau. 
**From  Blue  Print  Data  furnished  by  Mr.  Glenn  A.  Gray,  District  Engineer, 
Water  Resources  Branch,  U.  S.  G.  S. 


1 46  Report  on  the  Dam  at  Austin,  Texas. 

Some  of  the  data  used  are  of  such  a  nature  that  the  results  may  be  somewhat  in 
error;  but  in  general  it  is  believed  that  a  fair  degree  of  accuracy  has  been  attained. 
The  reliability  of  records  is  regarded  as  follows: 


(By  low  water  is  meant  a  discharge  of  less  than  500  sec.  ft.) 

Feb.  15,  1898 — June  7,  1899.    Low  water  records  reliable. 

June  8,  1899— Sept.  20,  1900.     Low  water  records  (below  400  sec.  ft.)  doubtful. 

This  affects  only  the  low  water    period  of  Sept.  1 — Oct.  27. 

Sept.  27,  1900— July  12,  1901.    Low  water  records  reliable. 

July  13,  1901 — Dec.  31,  1901.     Low  water  records  reliable. 

Jan.  1,  1902 — March  12,  1902.      Low  water  records  somewhat  doubtful.     Should 
perhaps  be  10  per  cent,  lower. 

Mar.  13,  1902— Feb.  26,  1903.      Low  water  records  reliable. 

Feb.  27,  1903— Oct.  4,  1903.     Low  water  records  somewhat  doubtful. 

Oct.  5,  1903— April  23,  1904.  Low  water  records  reliable.  (From  Apr.  5-23 
should  perhaps  be  10-15  per  cent,  higher.) 

Apr.  24,  1904 — Oct.  31, 1904.     Low  water  records  fairly  reliable. 

Nov.  1,  1904 — May  8,. 1905.     Low  water  records  reliable. 

May  9,  1905 — Oct.  9,  1905.  Low  water  records  reliable  (perhaps  somewhat  low). 

Oct.  10, 1905 — Aug.  11, 1906.     Low  water  records  fairly  reliable. 

Aug.  12,  1907 — Apr.  23,  1908.  Low  water  records  doubtful.  (Flow  perhaps 
more  rather  than  less  than  estimated.) 

Apr.  24,  1908— May  21,  1910.     Low  water  records  doubtful. 

May  21,  1910 — Sept.  9,  1910.      Low  water  records  reliable. 

Sept.  8,  1910 — May  9,  1913.     Low  water  records  doubtful. 

May  9,  1913 — Oct.  1,  1914.      Low  water  records  doubtful. 

Oct.  1,  1914— Sept.  1,  1917.    Eecords  reliable. 

Hydro  graphs  Based  on  the  Calculations  of  Stream  Flow. — Hydrographs  have 
been  platted  which  by  the  height  of  an  irregular  flow  line  above  a  horizontal  base  line 
show  graphically  the  varying  flow  of  the  stream  from  day  to  day.  As  only  a  small 
portion  of  the  high  water  flow  can  be  utilized  for  power  purposes,  the  hydrographs 
have  been  drawn  to  such  a  scale  that  the  low  water  flow  is  clearly  shown,  while  the 
high  water  flow  falls  above  the  diagrams  and  cannot  be  determined  therefrom.  Flood 
flows  are  not,  however,  essential  for  the  purpose  of  power  calculations,  except  in  the 
calculations  for  the  available  stored  supply. 

Power  Possibilities  Determined  from  Hydrographs. — The  hydrographs,  showing 
the  river  discharge  from  day  to  day  will  also  indicate  the  power  which  can  be  de- 
veloped from  day  to  day  from  this  flow  with  a  given  head.  If  the  flow  needed  to  de- 
velop a  given  power  is  determined,  a  comparison  of  the  power  demand  with  the  flow 


Storage.  1 47 

indicated  by  the  hydrograph  will  show  whether  or  not  there  was  sufficient  water 
from  day  to  day  to  deliver  the  amount  of  power  considered.  When  the  flow  line  of 
the  hydrograph  falls  below  the  power  line,  the  diagram  shows  that  the  flow  for  the 
day  or  days  so  indicated  was  not  sufficient  to  furnish  the  amount  of  power  consid- 
ered unless  the  deficiency  could  have  been  supplied  from  the  stored  water  above  the 
dam. 

Storage  Above  the  Dam. — The  determination  of  the  amount  of  storage  above 
the  dam  is  complicated  by  the  fact  that  no  accurate  surveys  are  available  from 
which  such  storage  can  be  determined.  Furthermore,  if  such  surveys  were  avail- 
able, the  storage  would  gradually  be  decreased  by  the  silting  up  of  the  reservoir  as 
occurred  from  1893  to  1900.  (See  page  49.) 

The  area  of  the  reservoir  above  the  dam  is  estimated  at  about  3000  acres  at  ele- 
vation 165,  and  at  about  2000  acres  at  elevation  160.  From  the  shape  of  the  basin, 
the  capacity  between  elevations  165  and  160  is  estimated  at  690,000,000  cubic  feet, 
and  by  drawing  the  reservoir  down  10  feet  additional  or  to  elevation  150,  an  added 
storage  of  a  similar  amount  is  estimated  as  available  for  power  purposes.  It  is 
further  estimated  that  there  is  an  additional  capacity  of  about  620,000,000  cubic  feet 
below  elevation  150  not  available  for  power  purposes  and  which  will  ultimately  be 
filled  with  silt.  The  total  capacity  of  the  reservoir  at  the  present  time  is  therefore 
about  2,000,000,000  cubic  feet,  1,300,000,000  cubic  feet  of  which  would  be  available 
with  65  foot  head  and  only  690,000,000  cubic  feet  of  which  would  be  available  if  a 
head  of  60  feet  was  utilized. 

As  some  of  the  pondage  will  undoubtedly  be  destroyed  by  the  silting  of  the  res- 
ervoir, the  effect  due  to  a  decrease  in  capacity  as  follows,  has  also  been  considered: 

Capacity  between  165  and  160 500,000,000  cu.  ft.      * 

Capacity  between  160  and  150  500,000,000  cu.  ft. 

Capacity  below  150  ..  250,000,000  cu.  ft. 


Total  Capacity   1,250,000,000  cu.  ft. 

Modification  of  HydrograpJis  Toy  Storage. — In  using  hydrograph  for  power  cal- 
culations, the  area  below  the  power  line  and  above  the  flow  line  of  the  hydrograph, 
showing  a  deficiency  in  the  flow  of  the  river  for  power  purposes,  so  far  as  power  es- 
timates are  concerned,  can  be  considered  as  filled  from  the  reservoir,  provided  the 
reservoir  is  full  and  to  the  extent  that  the  flood  flow  refills  the  reservoir. 

Deductions  from  the  Flow  at  the  Congress  Avenue  Bridge. — The  hydrographs 
used  are  based  on  flow  observations  at  the  Congress  Avenue  bridge,  as  previously 
noted.  The  flow  at  this  point  is  augmented  by  the  flow  of  Barton  Creek  and  by  the 
seepage  around  and  below  the  dam,  neither  of  which  would  be  available  for  power. 
In  addition  to  these  losses,  there  will  be  a  certain  evaporation  from  the  entire  sur- 
face of  the  lake  which  is  estimated  to  average  25  cubic  feet  per  second  with  the  res- 
ervoir elevation  at  165.  From  the  above  it  will  appear  that  there  must  be  certain 


148  Report  on  the  Dam   at  Austin,  Texas. 

deductions  from  the  flow  shown  by  the  hydrographs  before  the  remainder  can  be  con- 
sidered as  available  for  power.     These  deductions  have  been  estimated  as  follows : 

Barton  Creek 15  cu.  ft.  per  second 

Seepage 90  cu.  ft.  per  second 

Evaporation 25  cu.  ft.  per  second 


Total  Deductions 130  cu.  ft.  per  second 

Graphical  Representation. — In  each  hydrograph  these  deductions  have  been  in- 
dicated by  the  double  diagonal  cross  hatching  at  the  base  of  the  hydrograph  and  sub- 
tracted from  the  total  flow,  to  determine  the  amount  of  water  available  for  power.  On 
these  hydrographs  the  available  river  flow  is  indicated  by  cross  hatch  lines  inclined 
upward  to  the  right.  The  deficiency  in  the  river  flow  from  time  to  time  that  can  be 
supplied  by  the  water  stored  in  the  reservoir  is  indicated  by  cross  hatch  lines  in- 
clined downward  to  the  right.  The  amount  of  power  that  cannot  be  supplied  from 
water  storage  but  must  be  supplied  by  steam,  if  supplied  at  all,  is  indicated  by  hori- 
zontal and  vertical  cross  hatching.  From  a  a  study  of  these  hydrographs  from  month 
to  month  and  from  year  to  year,  the  available  power  of  the  river  for  each  year  has 
been  estimated. 

Power  Demand. — The  total  output  of  the  City's  electric  plant  in  1916  was  about 
4,000,000  kilowatt  hours  or  5,330,000  horse  power  hours,  and  the  steam  used  in  pump- 
ing would  probably  increase  this  to  about  7,300,000  HPH  or  practically  to  the  mini- 
mum amount  of  power  guaranteed  under  the  Johnson  contract.  If  the  hydraulic 
power  at  the  dam  can  be  safely  assured,  the  power  demands  at  Austin  will  undoubt- 
edly increase  and  a  consumption  of  at  least  double  the  present  demands  may  be  ex- 
pected within  a  few  years ;  and  with  the  rapid  growth  of  Austin,  the  utilization  of 
the  entire  capacity  of  the  plant  can  be  expected  within  a  short  term  of  years. 

Power  Calculations. — Based  on  the  above  consideration,  the  various  amounts  of 
power  available  under  heads  of  60  and  65  feet,  and  under  various  power  demands, 
have  been  calculated.  It  should  be  noted  that  these  calculations  have  been  made 
with  a  slide  rule,  and  in  some  cases  the  results  will  not  check  within  about  one  per 
cent.  The  degree  of  accuracy,  however,  is  greater  than  the  probable  accuracy  of  the 
stream  flow  data. 

Study  of  Minimum  Power  of  830  Horse  Power  or  600,000  Horse  Power  Hours 
Per  Month  of  30  Days. — A  study  of  the  hydrographs  indicates  that  with  a  65-foot 
head  and  under  the  assumption  made  above,  the  minimum  guaranteed  power  of 
600,000  HPH  per  month  or  7,200,000  HPH  per  year  (see  paragraph  11,  page  59) 
could  have  been  maintained  continuously  throughout  the  period  considered,  namely 
from  February,  1898  to  September,  1917. 

With  a  head  of  60  feet  the  same  amount  of  power  could  have  been  maintained 


Power  Calculations.  149 

during  the  same  period  except  for  certain  years  when  shortages  would  have  occur- 
red as  follows : 

Year  Shortage  In  Horse  Power  Hours 

1905  66,600 

1907  778,000 

1910 158,000 

1911  124,500 

1917  396,000 


Total    1,523,100 

Average  for  19y2  years   78,200  HPH 

Average  value  of  power  loss  per  annum,  due  to  reduction 

of  head  from  65'  to  60',  at  .9c  per  horse  power  hour  . . .     $704.00 

Study  of  the  Development  of  1650  Continuous  Horse  Power. — The  possibilities 
of  power  development  at  the  dam  have  also  been  investigated  for  a  continuous  out- 
put of  1650  horse  power  for  both  60  and  65  foot  heads,  and  the  amount  of  steam 
power  necessary  to  maintain  this  rate  of  output  has  been  estimated. 

Development  of  1650  Horse  Power  Under  65  Foot  Head. — The  condition  of  the 
development  of  1650  horse  power  under  65  foot  head,  and  the  necessary  steam  power 
to  maintain  this  output  during  low  water  conditions,  are  shown  on  the  hydrographs 
on  pages  150,  151  and  152.  The  estimates  made  from  these  hydrographs  are  also 
shown  in  detail  on  page  153. 

Development  of  1650  Horse  Power  under  60  Foot  Head. — Under  60  foot  head  the 
reduction  in  pondage  necessitates  an  increase  in  the  auxiliary  steam  power  neces- 
sary to  sustain  the  output  as  will  be  seen  by  an  examination  of  the  series  of  hydro- 
graphs  on  pages  154,  155  and  156,  and  of  the  detailed  estimates  on  page  157. 

Comparison  of  65  and  60  Foot  Heads  for  the  Development  of  1650  Continuous 
Horse  Power. — Abstracting  the  tables  for  65  and  60  foot  heads,  it  is  found  that  the 
amounts  of  power  which  would  be  developed  by  water  and  by  steam  under  the  con- 
ditions assumed  will  be  as  follows : 

The  total  horse  power  hours  per  year  at  1650  continuous  horse  power  are 
14,500,000. 

HPH  Water  HPH  Steam 

Average  at  60  Ft.  Head  12,921,000  1,617,000 

Average  at  65  Ft.  Head 13,980,000  598,000 


Average  Annual  Difference  in  Amount  of  Steam  Power  Used. .  .  .1,019,000  HPH 
Average  Annual  Value  at  0.9c  per  Horse  Power  Hour  $9,171.00 

It  is  apparent  that  if  the  interest  on  first  cost,  maintenance  cost  and  depreciation 
of  the  crest  gates  is  materially  less  than  $9,171  per  annum,  it  will  pay  to  maintain  the 


50 


Report  on  the  Dam  at  Austin,  Texas. 


/65O 


200 


Seepage ,  Evaporation  ancr  r/otv  of  Sarron  So 
XXXXXXXXXXXXXXXXXXXXXK  X 


/65O 


320 


zoo 


January      February      March  f)pri/  May  June 

Of 


Juty 


September   Ocfo&tr       November     December 


Stream  F/oiv. 


Seepaae,  efc. 


FlQUEE   84. 


Fbfiataae. 


Power  Calculations. 


151 


K45 
78S 


epoqf,  evaporation  ana/  r~/o>v  of  oarfon  Sprmq 


Seepage,   Evaporation  and  f~/o>r  of  Barfon  Sprino 
-  x  x  X  Xix  X  x  x  x  vXi*.  KX  x  x*  v  x"  K  x 


January 


eefafrona  of  rtijdrou/fc  RaMrr.  fohefooe  and  necessary  0vxi'//ary  Sfron 
rr  fo  Moi"t>'"'  ffSO  Continuous  fforst  foirrr  under  6JS  f&ff  Head. 


Seepage,  etc. 


fbndyqe- 


ffltxit/crry  Steam. 


FlGUBE    85. 


52 


Report  on  the  Dam     at  Austin,  Texas. 


S/orn 


1650 

/Z45 

735 

320 


1650 


4l?0 


zoo 


y////. 


Teenage,  Evaporation  and  f/ovr 

lL*.^X-^^.>i>.tXXXAXX*lxXA 


19/4 


>650    | 
,245  \ 


320 
0 


ZOO 


&I6 

/650 
#45 
780 
31O 
O 

Sce/xige,   Evaporation  ono'  f~/o>v  of  Barfoi* 
\                        \                       i 

Spring. 

January     February     rJarc/i 
t 

fff>r/7             May             June             Ju/y             &uyusS-      September    October 

firveoseaPr/s  or  cct-oe&oo  G/VF&  ar  fojsr/tj,  Texas. 

fjptver    fo  rfo/frfo/n  S65O  Gpn/rwotjs   fforsf  ftonvr   under  ffS  feet  fleacr1. 

November    December. 

'////////// 

X>VVVVVVVVV 

^$$^$ 

Sef/ooye.  etc. 


fftfxt/i'aro  Stean 


FlQUBE   86. 


Power  Calculations. 


153 


Showing  the  amount  of  hydraulic  power,  in  thousands  of  horse  power  hours,  which  could  have  been 
delivered  with  a  65  foot  head  by  the  Austin  hydraulic  power  plant  at  the  switchboard,  and  the  amount  of 
steam  power  necessary  to  maintain  1650  continuous  horse  power  during  the  years  1898  to  1917,  inclusive. 


Year 

Jan. 

Feb. 

Mch. 

Apr. 

May 

June 

July 

Aug. 

Sept. 

Oct. 

Nov. 

Dec. 

Annual 

Hydraulic    

1  235 

1  1% 

1  235 

1,196 

1,235 

1,235 

1,196 

1,235 

971 

1  004 

11  738 

189S 

Steam    

o 

o 

o 

0 

0 

o 

o 

o 

225 

231 

456 

Total    

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,1% 

1,235 

12,194 

Hvdraulic    

994 

906 

995 

1,041 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,1% 

1,235 

13,  699 

1899 

Steam    

241 

211 

240 

155 

0 

0 

0 

0 

0 

0 

0 

o 

847 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,196 

1,235 

13,  546 

Hydraulic    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,1% 

1,235 

14,546 

1900 

Steam    

0 

o 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,196 

1,235 

14,546 

Hydraulic    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,196 

1,235 

14,546 

19O1 

Steam    

0 

o 

o 

0 

0 

0 

0 

0 

0 

0 

0 

o 

0 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,546 

Plydraulic    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,  546 

1902 

Steam    

0 

0 

0 

o 

o 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,196 

1,235 

14,  546 

Hydraulic    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,546 

1903 

Steam    

0 

o 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,235 

1,117 

1,235 

1,  193 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,196 

1,235 

14,546 

Hydraulic    

1  235 

1  156 

1  235 

1  196 

1  235 

1,196 

1,235 

1,  235 

1,196 

1,235 

1,196 

1,235 

14,585 

19O4 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,235 

1,156 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,196 

1,235 

14,585 

Hydraulic    

1,235 

1,117 

1  235 

1  196 

1,235 

1,1% 

1,235 

1,226 

1,187 

1,235 

1,057 

865 

14,  019 

1905 

Steam    

0 

0 

0 

0 

o 

0 

0 

9 

9 

0 

139 

370 

527 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,546 

Hydraulic        .... 

875 

802 

914 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,196 

1,235 

13,550 

1906 

Steam    

360 

315 

321 

0 

0 

0 

0 

0 

0 

0 

0 

0 

996 

Total    

1,235 

1,117 

1,235 

1  196 

1  235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,546 

Hydraulic    

720 

645 

710 

706 

1  162 

1,196 

1,230 

1,191 

1,162 

1,235 

1,196 

1,235 

12,388 

1907 

Steam    

515 

472 

525 

490 

73 

0 

5 

44 

34 

0 

0 

0 

2,158 

Total    

1,235 

1,117 

1,235 

1,196 

1  235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,546 

Hydraulic    

1,235 

1,156 

1  235 

1  196 

1  235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,071 

14,421 

1008 

Steam    

0 

0 

0 

o 

o 

0 

0 

0 

0 

0 

0 

164 

164 

Total       

1  235 

1  156 

1  235 

1  196 

1  235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,196 

1,235 

14,585 

Hydraulic    

976 

867 

961 

937 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

13,504 

1909 

Steam    

259 

250 

274 

259 

o 

0 

0 

0 

0 

0 

0 

0 

1,042 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,546 

Hydraulic    

1,235 

1,117 

1,235 

1,196 

1,235 

1,066 

1,090 

1,090 

1,133 

1,148 

836 

846 

13,227 

1910 

Steam    

0 

o 

0 

0 

0 

130 

145 

145 

63 

87 

360 

389 

1,319 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,546 

Hydraulic    

851 

935 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,220 

1,181 

1,230 

13,945 

1911 

Steam    

384 

182 

0 

0 

0 

0 

0 

0 

0 

15 

15 

5 

601 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,  546 

Hydraulic    

1  235 

1  156 

1,235 

1  196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

981 

3.004 

14,139 

1912 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

215 

231 

446 

Total    

1,235 

1,156 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,196 

1,235 

14,585 

Hydraulic    

1  038 

931 

1,024 

1,013 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

13,769 

1913 

Steam    

197 

186 

211 

183 

0 

0 

0 

0 

0 

0 

0 

0 

777 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,546 

Hydraulic    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,196 

1,235 

14,546 

1914 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,  546 

Hydraulic    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,196 

1,235 

14,546 

1915 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,1% 

1,235 

1,1% 

1,235 

14,  546 

Hydraulic    

1,235 

1,156 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

927 

928 

14,009 

1916 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

269 

307 

576 

Total    

1,235 

1,156 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

1,196 

1,235 

1,196 

1,235 

14,585 

80S 

1  091 

1  196 

1  048 

980 

7,898 

QA7 

298 

144 

o 

187 

255 

1,776 

Total    

1,235 

1,117 

1,235 

1,196 

1,235 

1,196 

1,235 

1,235 

9.674 

Total    

21,  202 

19,475 

22,  822 

22,535 

24,483 

23,790 

24,363 

24,  247 

22,618 

23,363 

21,501 

21,768 

272,157 

Hyd'ic 

Period     

19 

19 

20 

20 

20 

20 

20 

20 

19 

19 

19 

19 

19.6 

Average    

1,116 

1,024 

1,141 

1,127 

1,224 

1,189 

1,218 

1,212 

1,190 

1,230 

1,131 

1,146 

13,  980 

Total    

2,263 

1,894 

1,878 

1,385 

217 

130 

337 

453 

106 

102 

1,223 

1,697 

11,685 

Steam 

Period    

19 

19 

20 

20 

20 

20 

20 

20 

19 

19 

19 

19 

19.5 

Average    

119 

100 

94 

69 

11 

7 

17 

23 

6 

5 

65 

89 

598 

Hydraulic    
Steam    

1,116 
119 

1,024 
100 

1,141 
94 

1,127 
69 

1,224 
11 

1.189 
7 

1,218 
17 

1,212 
23 

1,190 
6 

1,230 
5 

1,131 
65 

1,146 
89 

13,980 
598 

Total    

1,235 

1,124 

1,235 

1,196 

1,235 

1.196 

1,235 

1,235 

1,196 

1,235 

1,196 

1,235 

14,  578 

t   Hydraulic   .. 
Steam  

90.4 
9.6 

91.1 
8.9 

92.4 
7.6 

94.2 
5.8 

99.1 
0.9 

99.4 
0.6 

98.6 
1.4 

98.1 
1.9 

99.5 
0.5 

99.6 
0.4 

94.6 
5.4 

92.8 
7.2 

95.9 
4.1 

154 


Report  on  the  Dam  at  Austin,  Texas. 


320 


*  <3OO 


POO 


600 


4OQ 


200 


400 


ZOO 


600 


.fc  ZOO 


eoo 


4OO 


:'^^^  -^88888^  888^8  88888^ 


Seepage,  frojooraf/ov  onaf  f/oir  of  Sorfon  Spring 
•- 


(s  <o 


February      Marcri 


ffream  r7&>* 


May 


June  Ju/if 


Sepfember    October        Movemiier     December 


or 

ofrofta  of  rftfCfrovt'o  f&vrtr,  ftonc/oy*  ortcf  nece*9on/  Gt*e//f&ry  Sfeom 
to  My/ri 'for'fr  /6SO  Gyr>tiinv0u9  Horye  Power  (/rraffr  60  feef  ffeao1 


Serjoaye.  era. 


FlGUBE   87. 


ary  3 f earn 


Power  Calculations. 


55 


too 


/650 


•$  600 
I 


ZOO 


6OO 


4OO 


ZOO 


400 


zoo 


, '//////,  Y/////,  W////,  Y//////  7/77 //, 


Seepage,   evaporation  and  f/ov  of  3arfon  Spring) 
<  XXXXAx1>Ay\y^xNXXX  XXXXXXXXAAXXXX 


K///A  Y//////AY/////Y/////M 


eepage,   Eva/oorartofr  and  f/of  of  Barfon  Spring 
>(XXxW^vV  .AAAXXX*.  X 


Seepage,  Fvapo/~cr//of?  and  F/ow  of   Sarfon  5pr 


Y///////////S 


Seepage,  Cvaporafion  crnal  f/oir  of  Barfon  Spring. 
k  ' 


Seepage,  ^aporof/on  ana>  f/o»  Of  Barton  Spring 


September   October       November     December 


January      february     March  ffpri/ 


32O 


ring   ff*/ationa  of  Hya'rou/'c  Reiver,  f&ndaae  and  necessary  0vxi//ary  Sfeon? 
Power  to  sfainfoin  /f£0  Confihvota  fforae  nurtr  under  60  fee/  Mead. 


FIGURE  88. 


56 


Report  on  the  Dam  at  Austin,  Texas. 


6OO 


400 


eoo 


1918 

/650 
IZ4S 
706 
320 
O 

Sf 

«**••  fya' 

yorat/on  or* 

• 

*  /%>»•  of  0 

7 

January     February 


ffjsri/  Mat/  */u/?ff  •jfc'/y  fft/qu&t       3e/?Aes??6er     0G/06er        Mere/rro*/-    0ecem£*er. 

OF    COIO2APO    &/V&2  0T  avST/Nt 

'ona'a&e  arrd  rtfCf-Ayffr-y  &u*/ 
ffor&e  &0>*w  (Sf*c/fr  00   feef 


Ponc/ay*. 


FlGUBE   89, 


Power  Calculations. 


157 


Showing  the  amount  of  hydraulic  power,  in  thousands  of  horse  power  hours,  which  could  have  been 
delivered  with  a  60  foot  head  by  the  Austin  hydraulic  power  plant  at  the  switchboard,  and  the  amount  of 
steam  power  necessary  to  maintain  1650  continuous  horse  power  during  the  years  1898  to  1917,  inclusive. 


Year 

Jan. 

Feb. 

Men. 

Apr. 

May 

June 

July 

Aug. 

Sept. 

Oct. 

Nov. 

Dec. 

Annual 

Hydraulic    

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,076 

765 

757 

11,116 

1898 

0 

0 

0 

0 

0 

0 

0 

158 

429 

477 

1,064 

Total 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

12,180 

Hydraulic    

748 

673 

757 

880 

1,234 

1,194 

1,234 

1,040 

832 

908 

1,194 

1,234 

11,928 

1S99 

Steam    

486 

442 

477 

314 

0 

0 

0 

194 

362 

326 

0 

0 

2,601 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,  529 

Hydraulic        .... 

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,  529 

190O 

0 

o 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,  529 

Hydraulic      

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,529 

1901 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,523 

Hydraulic       .... 

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,529 

1902 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,529 

Hydraulic    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,110 

1,075 

14,286 

1903 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

84 

159 

243 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,529 

Hydraulic    

1,101 

1,025 

1,102 

1,098 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,083 

1,058 

13,791 

1904 

133 

127 

132 

96 

0 

0 

0  . 

0 

0 

0 

111 

176 

775 

Total    

1,234 

1,115 

1,234 

1,194 

1^.234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,566 

1,043 

944 

1,186 

1,194 

1  234 

1,194 

1,234 

1,172 

1,129 

1,234 

956 

583 

13,108 

1905 

Steam    

191 

171 

48 

0 

0 

0 

0 

62 

65 

0 

238 

646 

1,421 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,23' 

l,19i 

1,234 

1,194 

1,234 

14,529 

Hydraulic    

575 

514 

659 

1,159 

1,234 

1,194 

1,234 

1,234 

1,194 

1,141 

1,070 

1,186 

12,394 

1906 

Steam       

659 

601 

575 

35 

0 

0 

0 

0 

0 

93 

124 

48 

2,135 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,  529 

455 

395 

437 

430 

1,110 

1,194 

1,221 

743 

614 

1,234 

1,194 

1,234 

10,261 

1907 

Steam    

779 

720 

797 

764 

124 

0 

13 

491 

580 

0 

0 

0 

4,268 

Total    

1,234 

1,115 

1,234 

1,194 

1,233 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,  529 

1  234 

1,152 

1,234 

1,194 

1,  234 

1,104 

1,234 

1,234 

1,194 

1,234 

1,194 

996 

14,328 

1908 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

238 

238 

Total    

1,234 

1,152 

1,234 

1,194 

1,234 

1,194 

1,234 

1,23' 

1,194 

1,234 

1,194 

1,234 

14,566 

Hydraulic    

721 

567 

617 

633 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

12,290 

1909 

513 

548 

617 

561 

0 

-Q 

0 

0 

0 

0 

0 

0 

2,239 

Total 

1  234 

1  115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,529 

Hydraulic    

1,004 

881 

987 

1,194 

1,  234 

765 

730 

730 

1,003 

1,062 

543 

530 

10,  667 

1910 

Steam    

230 

230 

247 

0 

0 

429 

504 

504 

191 

172 

651 

704 

3,862 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,529 

Hydraulic    

531 

787 

1,234 

1,194 

1,097 

756 

995 

1,234 

1,194 

818 

694 

1,013 

11,547 

1911 

Steam   •  

703 

328 

0 

0 

137 

438 

239 

0 

0 

416 

500 

221 

2,982 

Total        

1,234 

1,115 

1,234 

1,194 

1,234 

1.194 

1,234 

1,23' 

1,194 

1,234 

1,194 

1,224 

14,429 

Hydraulic    

1,102 

1,073 

1,234 

1,194 

1,234 

1,194 

933 

916 

880 

1,070 

788 

801 

12,419 

1912 

132 

79 

0 

0 

0 

0 

301 

318 

314 

164 

406 

433 

2,147 

Total 

1  234 

1,152 

1,234 

1,194 

1,234 

1,194 

1,234 

1,23' 

1,194 

1,234 

1,194 

1,234 

14,566 

Hydraulic    

801 

731 

810 

804 

1,234 

1.194 

1,190 

983 

1,061 

1,234 

1,194 

1,234 

12,470 

1913 

Steam    

433 

384 

424 

390 

0 

0 

44 

251 

13? 

0 

0 

0 

2,059 

Total 

1  234 

1  115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,23' 

1,194 

1,234 

1,194 

1,234 

14,529 

Hydraulic    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,529 

1914 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,23' 

1,194 

1,23' 

1,194 

1,234 

14,529 

Hydraulic    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,529 

1915 

Steam    

0 

0 

0 

•  0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

Total    

1,234 

1,115 

1,234 

1,194 

1,234 

1,194 

1,234 

1,23' 

1,19< 

1,23' 

1,194 

1,234 

14,529 

Hydraulic    

1,234 

1,152 

1,234 

1,194 

1,234 

1,194 

1,225 

900 

867 

1,026 

752 

708 

12,720 

1916 

Steam    

0 

0 

0 

0 

0 

0 

9 

33' 

327 

208 

442 

526 

1,846 

Total 

1  234 

1  152 

1,234 

1,194 

1,234 

1,194 

1,234 

1,23' 

1,194 

1,23' 

1,194 

1,234 

14,566 

717 

647 

712 

690 

1  000 

1,194 

650 

374 

5  974 

1917 

Steam 

517 

468 

522 

504 

234 

0 

584 

860 

3,689 

Total 

1  234 

1  115 

1  234 

1  194 

1,234 

1,194 

1,234 

1,234 

9,663 

Total    

18,670 

17,235 

20,  841 

21,21)6 

24,  185 

23,  013 

22,986 

21,  666 

20,714 

21,909 

19,701 

19,  818 

251,  954 

Hyd'ic 

Period      

19 

19 

20 

20 

20 

20 

20 

20 

19 

13 

19 

19 

19.5 

983 

906 

1,042 

1,061 

1,209 

1,151 

1,149 

1,084 

1,090 

1,153 

1,037 

1,043 

12,921 

Total    

4,776 

4,098 

3,839 

2,664 

495 

867 

1,694 

3,014 

1,972 

1,537 

2,985 

3,628 

31,569 

Steam 

Period    

19 

19 

20 

20 

20 

20 

20 

20 

IS 

IS 

19 

19 

19.5 

Average    

251 

215 

192 

133 

25 

43 

85 

150 

104 

81 

157 

191 

1,617 

Hydraulic    
Steam    

983 
251 

906 
215 

1,042 
192 

1,061 
133 

1,209 
25 

1,151 
43 

1,149 

85 

1,084 
150 

1,090 
104 

1,153 
81 

1,037 
157 

1,043 
191 

12,921 
1,617 

Total 

1  234 

1  121 

1  234 

1  194 

1,234 

1,194 

1,234 

1,234 

1,194 

1,234 

1,194 

1,234 

14,538 

t   Hydraulic   .. 
Steam  

79.7 
20.3 

80.8 
19.2 

84.5 
15.5 

88.8 
11.2 

98.0 
2.0 

96.4 
3.6 

93.1 
6.9 

87.8 
12.2 

91.3 

8.7 

93.4 
6.6 

86.8 
13.2 

84.5 
15.5 

88.9 
11.1 

1 58  Report  on  the  Dam  at  Austin,  Texas. 

head  at  65  rather  than  at  60  feet  with  a  development  of  1650  horse  power,  but  that  if 
the  annual  cost  is  equal  to  or  greater  than  this  amount,  there  will  be  no  logical  rea- 
son for  the  increased  head. 

Interest  should  be  taken  at  5  per  cent.  The  annual  cost  of  maintenance  and  the 
depreciation  of  such  gates  can  hardly  be  taken  at  less  than  10  per  cent.  The  capi- 
talized annual  saving  due  to  a  65-foot  head  may  therefore  be  estimated  on  a  15  per 
cent,  basis  at  $61,140.  To  this  should  be  added  the  cost  of  raising  the  crest  to  eleva- 
tion 160  feet,  which  is  estimated  at  $53,000,  making  a  total  of  $114,140,  which  is  the 
maximum  that  can  be  expended  to  advantage  for  increasing  the  head  from  60  to  65 
feet,  with  a  capacity  of  1650  horse  power. 

Study  of  the  Development  of  3300  Continuous  Horse  Power. — The  ultimate  de- 
velopment of  the  power  plant  at  the  Austin  dam  as  now  designed  anticipates  the 
output  of  3300  horse  power.  This  condition  has  also  been  investigated  for  both  65 
and  60  foot  heads. 

Development  of  3300  Horse  Power  Under  65  Foot  Head. — The  conditions  that 
will  obtain  under  a  65-foot  development  and  a  continuous  output  of  3300  horse  power 
are  shown  on  pages  159  to  163  inclusive,  and  the  detailed  estimates  are  shown  on  page 
164. 

Development  of  3300  Horse  Power  Under  60  Foot  Head. — The  same  studies  for  a 
60-foot  development  are  shown  on  pages  165  to  169  inclusive,  and  the  detailed  esti- 
mates are  shown  on  page  170. 

Comparison  of  65  and  60  Foot  Heads  for  the  Development  of  3300  Continuous 
Horse  Power. — Abstracting  the  table  for  65  and  60  foot  heads,  the  total  horse  power 
hours  per  year  are  found  to  be  approximately  29,200,000,  and  the  comparisons  to  be 
as  follows: 

HPH  Water  HPH  Steam 

Average  at  60  Foot  Head 21,300,000  7,900,000 

Average  at  65  Foot  Head 23,290,000  5,650,000 


Average  Annual  Difference  in  Amount  of  Steam  Power  Used  . . .     2,2 50,000  HPH 
Average  Annual  Value  of  Steam  Power  at  0.9c  per  Horse  Power 

Hour $20,250.00 

With  interest  at  5  per  cent,  and  depreciation  and  maintenance  at  10  per  cent,  the 
capitalized  value  of  the  extra  5-foot  head  is  essentially  $135,000.  To  this,  for  com- 
parison, should  be  added  the  cost  of  removing  piers  and  building  up  the  hollow  sec- 
tion to  60  feet,  amounting  to  $53,000,  and  making  the  total  difference  in  favor  of  the 
65  foot  dam  $188,000,  which  is  the  total  amount  which  can  now  be  expended  to  secure 
the  extra  5-foot  head.  To  make  the  65-foot  head  profitable,  the  expense  should  be  less 
than  the  amount  named  as  with  this  expenditure  the  returns  would  equal  only  the 
estimated  annual  expense. 


Power  Calculations. 


159 


850 

350 


January     February      March  ffpri/  May  Ju, 


Sep/ember    October       A/ore/nber     December 


e/vee  #T  flusr/N,  Texas. 


Sfream  f/on-. 


e.  efc-  Pondoqe 

FlQUBE  90. 


y  S/eym. 


160 


Report  on  the  Dam  at  Austin,  Texas. 


Setfioae.  Evaporation  and  f/o#  of  Sorton    Spring. 


350 


January  •   fetwary      Marcri  ffpr/'J  May  June  Ju/tf  fiuo/us/       Sepfffntef'    Ocfo&er        Movembtr 

Of 


Seepage,  tfo. 


FlQUBE   91. 


Power  Calculations. 


161 


3300 


Z35O 

I860 


850 
350 


January      February      March  ffpri/  May  June  July  august        September    October        November     Cecemder 

OF  COLOgfiPO  e/V££  ffr  ffUST/M, 

Onrtno    getatioru  of  fftfafrais/fc  Power.  Poncfage  &*&  neccasory  Gux/'/t'ary 
Po#er  fo  M0/'rjfa'/r>  33O0  Corrfinuoos  fforse  Pother   vna/er  C5  ffffff  Sfeao. 


Sfreom  F/o>v.  3ec.?J?f. efo.  POncfaye 

FIGURE  92. 


162 


Report   on   the   Dam   at  Austin,   Texas. 


§.'000 


zoo 


8OO 


600 


4OO 


850 
350 


January      Fttwi/orij      rlorcn  0pri/ 


September    October        November      December 

_  „   0/vre  ar  ausr/N,  Tfxas. 

Sftoirinq   Ke/attoru  of  Hyc/roulic  Ftonrer,  Ponctaqe  or>&  necessary  av*i/iory   Steart 
Power  to  Maintain  33OO  Continuous   Hone  Po*tr  urx/tr  fi  feet  Mead 


Stream  rtov 


3ee/aaiff.  rfc 


avxi//onf  Steam 


FlQUBE   93. 


Power  Calculations. 


163 


3300 


^lOOO 


SOO 


4OO 


January      February 


flpri/  May  June  Ji/ty 

of  coweapo 

n33OO 


Sepfember    Ocfoder        Movem&er      December 


FIGURE  94. 


164 


Report   on   the   Dam   at  Austin,   Texas. 


Showing  the  amount  of  hydraulic  power,  in  thousands  of  horse  power  hours,  which  could  have  been 
delivered  with  a  65  foot  head  by  the  Austin  hydraulic  power  plant  at  the  switchboard,  and  the  amount  of 
steam  power  necessary  to  maintain  3300  continuous  horse  power  during  the  years  1898  to  1917,  inclusive. 


Year 

Jan. 

Feb. 

Men. 

Apr. 

May 

June 

July 

Aug. 

Sept. 

Oct. 

Nov. 

Dec. 

Annual 

Hydraulic    

2,455 

0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,160 
295 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,417 
38 
2,455 

2.10S 
347 
2,455 

2,161 
294 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,762 
693 
2,455 

2,37: 

0 
2,375 

2,375 
0 
2,375 

2,375 

0 
2,375 

2,37 
0 
2,37 

2,37 
0 
2,37 

2,37 
0 
2,375 

2,375 
0 
2,375 

2,37a 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

1,089 
1,286 
2,375 

1,352 

1,023 

2,456 
0 
2,45 

2,45 
0 
2,45 

2,455 
0 
2,45 

2,455 
0 
2,455 

2,45 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,267 
188 
2,455 

2,455 
0 

2,455 

2,455 
0 

2,455 

1,100 
1,355 
2,455 

1,802 
653 
2,455 

1,322 
1,133 
2,455 

1,955 
500 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

1,850 
605 
2,455 

1,355 
1,100 
2,455 

2,45 
0 
2,455 

1,48 
96 
2,45 

2,45 
0 
2,45 

2,455 
0 
2,455 

2,45 
0 
2,455 

2,455 
0 

2,455 

2,455 
0 
2,455 

1,951 

2,375 
0 
2,375 

1,248 
1,127 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

1,616 

759 
2,375 

2,375 
0 
2,375 

1,208 
1,167 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

1,430 
945 
2,375 

1,982 
393 
2,375 

1,257 
1,118 
2,375 

2,063 
307 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

1,295 
1,080 
2,375 

1,230 

1,22 
2,45 

1,47 
98 
2,455 

2,45 
0 
2,45 

2,45 
0 
2,455 

2,455 
0 
2,455 

2,176 

27 
2,455 

2,455 
0 
2,455 

1,677 
778 
2,455 

1,855 
600 
2,455 

2  311 

97 
1,40 
2,37 

2,37 
0 
2,37 

2,37 
0 
2,37 

2,15 
22 
2,37 

2,37 
0 
2,37 

1,419 

958 

996 
1,458 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

1,802 
653 
2,455 

2,455 
0 
2,455 

1,455 

1,000 
2,455 

1    QOQ 

15,311 

4,089 
19,  400 

20,  642 
8,263 
28.905 

28,  905 
0 
28,905 

28,027 
878 
28,  905 

27,  377 
1,528 
28,  905 

26,  670 
2,235 
28,905 

23,109 
5,871 
28,  980 

21,517 
7,388 
28,905 

21,666 
7,239 
28,  905 

19,071 
9,834 
28,  905 

26,  538 
2,442 
28,980 

22,902 
6,003 
28,905 

17,191 
11,714 
28,  905 

20.992 
7,913 
28,905 

18,982 
10,098 
28,980 

21,810 
7,095 
28,905 

28,905 
0 
28,905 

28,905 
0 
28,905 

21,628 
7,352 
28,980 

10,038 
9,207 
19,245 

1898      Steam    

;  Total    

'  Hydraulic    

995 
1,460 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

1,801 

654 
2,455 

2,455 
0 
2,455 

1,383 

1,072 
2,455 

1,400 
1,055 
2,455 

750 

1,705 
2,455 

698 
1,757 
2,455 

2,348 
107 
2,455 

914 
1,541 
2,455 

1,413 

1,042 
2,455 

835 
1,620 
2,455 

1,781 
674 
2,455 

1,027 
1,428 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,311 
144 
2,455 

928 
1,527 
2,455 

898 
1,322 
2,220 

2,220 
0 
2,220 

2,220 
0 
2,220 

1,643 

577 
2,220 

2,220 
0 
2,220 

1,282 
1  013 

l.OOC 
1,45 
2,45 

2,456 
0 
2.4K 

2,455 
0 
2,455 

2,177 

278 
2,455 

2,455 
0 
2,455 

1,383 

1,072 
2,455 

1,937 
518 
2,455 

818 
1,637 
2,455 

707 
1,748 
2,455 

2,345 
110 
2,455 

865 
1,590 
2,455 

1,418 
1,037 
2,455 

2,455 
0 

2,455 

1,777 

678 
2,455 

1,027 
1,428 
2,455 

2,455 
0 

2,455 

2,455 
0 
2,455 

2,267 
1?8 
2,455 

923 
1,532 
2,455 

1,42 
95 
2,37 

2,37 
0 
2,37 

2,37 
0 
2,375 

2,356 
18 
2,375 

2,375 
0 
2,375 

1,578 
797 
2,375 

2,375 
0 
2,375 

1,680 
695 
2,375 

6SO 
1,695 
2,375 

2,327 

48 
2,375 

945 

1,430 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,040 
335 
2,375 

1,085 
1,290 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

887 
1,488 
2,375 

1809     Steam    

Total    

Hydraulic    

1900     Steam    

Total    

Hydraulic    

1901     Steam    

Total    

Hydraulic    
1902     Steam    

Total    

i  Hydraulic    

1903     Steam    

Total    

Hydraulic    

1,520 
855 
2,375 

1,257 
1,11 
2,375 

1,665 

710 
2,375 

2,375 
0 
2,375 

1,737 
638 
2,375 

2,375 
0 
2,375 

1,550 
825 
2,375 

1,165 

1,210 
2,375 

970 
1,405 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

965 
1,410 
2,375 

1904     Steam    

1,062 
2,455 

755 
1,700 
2,455 

2,100 
355 
2,455 

2,455 
0 
2,455 

1,003 
1,452 
2,455 

2,455 
0 
2,455 

855 
1,600 
2,455 

1,858 

597 
2,455 

1,023 
1,432 
2,455 

2,455 
0 

2,455 

2,455 
0 

2,455 

2,455 
0 
2,455 

928 
1,527 
2,455 

;  Total    

2,295 

1,264 

956 
2,220 

683 
1,537 
2,220 

635 

1,585 
2,220 

2,208 
87 
2,295 

778 
1,442 
2,220 

1,295 
924 
2,220 

1,355 

865 
2,220 

1,670 
625 
2,295 

933 
1,287 
2,220 

2,220 
0 
2,220 

2,220 
0 
2,220 

2,165 
130 
2,295 

837 
1,383 
2,220 

Hydraulic    

1905     Steam    

504 
2,455 

2,455 
0 

2,455 

1,200 
1,255 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

1,096 
1,359 
2,455 

2,455 
0 
2,455 

1,397 
1,158 
2,455 

1,600 
855 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

1,354 
1,101 
2,455 

971 

1,484 
2,455 

Total    

Hydraulic    

1906     Steam    

Total    

Hydraulic    

1907     Steam 

144 

Total    

2,455 

2,455 
0 

2,455 

2,455 
0 

2,455 

1,152 

1,303 
2,455 

1,250 
1,205 
2,455 

1,622 
833 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

2,455 
0 
2,455 

1,719 
736 
2,455 

Hydraulic    

1908     Steam    

Total    

'  Hydraulic    

1909     Steam    

Total    

Hydraulic    

1910     Steam    

Total    

Hydraulic    

1911     Steam    

Total    

2,375 

1,962 
413 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

2,375 
0 
2,375 

1,944 
431 
2,375 

2,375 
0 
2,375 

1  Hydraulic    .... 

1912     Steam    

Total    

Hydraulic    

1913     Steam    

Total    

Hydraulic    

1914     Steam    

Total    

Hydraulic    

1915     Steam    

Total    

'  Hydraulic    

1916     Steam     

Total    

Hydraulic    

1917     Steam    

Total    

Total    

30,  859 

19 
1,623 
15,786 

19 
832 
1,623 
832 
2,455 
66.1 
33.9 

28,746 

19 
1,513 
13,733 

19 
723 
1,513 
723 
2,236 
67.6 
32.4 

33,  374 

19 
1,757 
13,271 

19 

698 
1,757 
698 
2,455 
71.5 
28.5 

36,377 

19 
1,915 

8,748 

19 
460 
1,915 
460 
2,375 
80.6 
19.4 

47,433 

20 
2,372 
1,667 

20 
83 
2,372 
83 
2,455 
96.6 
3.4 

44,347 

20 
2,217 
3,153 

20 
158 
2,217 
158 
2,375 
93.3 
6.7 

43,566 

20 
2,178 
5,534 

20 
277 
2,178 
277 
2,455 
88.7 
11.3 

40,  517 

20 
2,026 
8,683 

20 
434 
2,026 
434 
2,460 
82.3 
17.7 

38,  229 

19 

2,012 
6,896 

19 
363 
2,012 
363 
2,375 
84.7 
15.3 

38,561 

19 
2,029 
8,084 

19 
426 
2,029 
426 
2,455 
82.6 
17.4 

34,368 

19 

1,808 
10,757 

19 
567 
1,808 
567 
2,375 
76.1 
23.9 

33,808 

19 
1,779 
12,837 

19 
676 
1,779 
676 
2,455 
72.4 
27.6 

450,185 

19,333 
23,290 
109,149 

19,333 
5,650 
23,290 
5,650 
28,  940 
80.5 
19.5 

Hyd'c    Period    

'  Average    

|  Total    

Ste'm    Period   

Average    

1  Hydraulic    

i  Total   

I  %  Hydraulic  — 
i  %  Steam   

Power  Calculations. 


165 


Seepage,  Evaporation  ancf  /"Sow  of  Borfcm    Spring 


Septemtw    October        SS0i/emt>er      Oecemtier 


January 


Stream  f/prr. 


Sffpoar,  ere. 


FIGURE  95. 


166 


Report  on  the  Dam   at  Austin,   Texas. 


1200 


Y////////// 


Y///Y//////////////////, 


Y/W//////////, 


735 


At/aus/       September    Oc/oeer 

or  coweaoo  eiYte  tfrrJusr/N,  Texas. 

fr/afior>f  -of  rfyctroo/ic   fbirrr,    fbniSoor  and  ntcessoru  0u*i'//or<f  Jfa 
*er  *  Maintain  3300  Cont/'nuout   ftonc  Potvtr  unc/tr  eo  reef  r/ead. 


Seepage.  «fe.  ftortofaife  ^Box/Vary  aftara 

FlGUBE   96. 


Power  Calculations. 


167 


Seepage.  Fya/oorof/ort  and  f~/o*r  of  Sarfon    Sprint} 


Ju/y  ffuyuar        Sep/embtr     Of/ooer        S/ovemticr      Becember 


February        tjffrc*>  ffprit  May 


-TS5 


miiy    eefaftor*3   of  rtyctraut/c  tforrfr.    Penc/aqrr   one?  fteceasortf  GtsMtttory  Sffa 
PQ~rr  to  rloinfoin  33OO  CQnftnvOv^  '  fforsc  Poirer  an&er  6O   reer  Heoc/, 


See/serge,  ete.  forto/ayf  ffvf/7/ary  Sfrar*. 

FlQUBE   97. 


168 


Report  on  the  Dam   at  Austin,   Texas. 


SttOHrmy    &*/a*i0n6    of  flydratstic  &O"*',    Poic/ay*   or>&  "rcessory  **vxf"ary   j 
Pother  fo  /*fo*s>fQ/r7  330O  Cont»?vOu3   Morse  f*ower  under  €0  feet  rteact. 


rtcfo?*    as>&  r>*ce&sortj  0tSJ(i//'ortf    $fifo 


Seepage,  efc 


"ana/age 


Power  Calculations. 


169 


February      March  April  May  June  Ju/y 


3ef>f-emi>er    October       JVovemter     Oecemhtr 


winq     Gelations    of  rtyCfrauhc  Power,    Forrdotfe   ana/  r>ecf&3ori/  0tfjr/t/arrc/   J 
Power  fff  -rto-infairt  33OO  Corrfirtvoua   rforje  Porver   uncftr  60  feet  r/faot 


Seepage,  efc.  Pyno/aqe  OuxWarif  Sftam, 

FlGUEE   99. 


170 


Report   on  the  Darn   at   Austin,   Texas. 


Showing  the  amount  of  hydraulic  power,  in  thousands  of  horse  power  hours,  which  could  have  been 
delivered  with  a  60  foot  head  by  the  Austin  hydraulic  power  plant,  at  the  switchboard,  and  the  amount  of 
steam  power  necessary  to  maintain  3300  continuous  horse  power  during  the  years  1898  to  1917,  inclusive. 


Year 

Jan. 

Feb. 

Mch. 

Apr. 

May 

June 

July 

Aug. 

Sept. 

Oct. 

Nov. 

Dec. 

Annual 

Hydraulic    

1,134 

1,878 

2,480 

2,400 

2,230 

1,945 

2,020 

1,140 

764 

764 

16  755 

1898 

Steam    

1,346 

522 

0 

0 

250 

535 

380 

1  340 

1  636 

1  716 

7  795 

Total    

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2,400 

2  480 

24  480 

Hydraulic    

750 

697 

754 

1,275 

2,480 

2,400 

2,480 

1,193 

880 

1,044 

2,320 

2  480 

18  753 

1899 

Steam       

1  730 

1,543 

1,726 

1,125 

0 

0 

0 

1,287 

1,520 

1  436 

80 

0 

10  447 

Total    

2,480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2,400 

2  480 

29  200 

Hydraulic    

2,480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2  400 

2  480 

29  200 

19OO 

Steam    

0 

0 

0 

0 

0 

0 

0 

0 

o 

o 

o 

o 

o 

Total    

2,480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2,400 

2  480 

29  200 

Hydraulic    

2,480 

2,240 

2,480 

2,400 

2,480 

2,016 

2,165 

1,935 

2,080 

1  802 

1  906 

1  417 

25  401 

1901 

Steam    

0 

0 

0 

0 

0 

384 

315 

545 

320 

678 

494 

1  063 

3  799 

Total    

2,480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2  400 

2  480 

29  200 

1902 

Hydraulic    
Steam    

1,432 
1,048 

1,275 
965 

1,898 

582 

2,300 
100 

2,480 
0 

2,072 
328 

2,480 
0 

2,480 

o 

2,400 

o 

2,076 
404 

1,823 

577 

2,480 

o 

25,106 
4  004 

Total       

2  480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2  480 

2  400 

2  480 

2  400 

2  480 

29  200 

Hydraulic    

2,480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2,352 

2  295 

2  126 

1  126 

1  080 

25  939 

1903 

Steam    

0 

0 

0 

0 

0 

0 

c 

128 

105 

354 

1  274 

1  400 

3  261 

Total    

2,480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2  400 

2  480 

29  200 

1904 

Hydraulic    
Steam  

1,087 
1,393 

1,050 
1,270 

1,126 
1,354 

1,432 
968 

2,480 
0 

2,400 
0 

2,440 
40 

2,240 
240 

2,355 
45 

2,480 
0 

1,260 
1,140 

1,060 
1  420 

21.  410 
7  870 

Total    

2,480 

2,320 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2  400 

2  480 

29  280 

1905 

Hydraulic    
Steam    

1,043 
1,437 

955 
1,285 

1,850 
630 

2,400 
0 

2,480 
0 

2,400 
0 

2,480 
0 

1,637 
843 

1,282 
1  118 

1,544 
936 

1,278 
1  122 

570 
1  910 

19,  919 
9  281 

Total    

2,480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2  480 

2  400 

2  480 

29  200 

1906 

Hydraulic    
Steam    

627 
1,853 

560 
1,680 

685 
1,795 

1,600 
800 

2,080 
400 

2,400 
0 

2,480 
0 

2,480 
0 

2,400 
0 

1,418 
1,062 

1,075 
1  325 

1,900 
580 

19,  705 
9  495 

Total    

2,480 

2,240 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2  400 

2  480 

2  400 

2  480 

29  200 

1907 

Hydraulic    
Steam    

460 
2,020 

390 
1,850 

440 
2,040 

428 
1,972 

2,129 
351 

2,400 
0 

2,280 
200 

743 
1,737 

640 
1,760 

2,310 
170 

2,400 
0 

2,458 
22 

17,078 
12  122 

Total       

2  480 

2,24 

2,480 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2,400 

2  480 

29  200 

1908 

Hydraulic    
Steam    

1,910 
570 

1,84 
480 

1,855 
625 

2,115 

285 

2,480 
0 

2,400 
0 

2,480 
0 

2,480 
0 

2,400 
0 

2,480 
0 

1,605 
795 

775 

1,705 

24,820 
4  460 

Total    

2  480 

2,32 

2,48 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2,400 

2,480 

29  280 

190 

Hydraulic    
Steam    

610 

1,870 

56 
1,68 

625 

1,855 

710 
1,690 

2,480 
0 

2,400 
0 

2,480 
0 

2,46 
13 

2,360 
4 

2,480 
0 

2,400 
0 

2,480 
0 

22,052 
7,148 

Total    

2,480 

2,24 

2,48 

2,400 

2,480 

2,400 

2,480 

2,480 

2,400 

2,480 

2,400 

2,480 

29,  200 

191 

Hydraulic    
Steam    

1,013 
1  467 

883 
1,35 

97 
1,507 

2,320 

8 

2,267 
213 

77 
1,624 

742 

1,738 

73 

1,744 

1,28 
1,112 

1,070 
1,410 

527 

1,873 

533 

1,947 

13,  128 
16,  072 

Total    

2,48 

2,24 

2,48 

2,400 

2,480 

2,400 

2,48 

2,48 

2,400 

2,480 

2,400 

2,48 

29,200 

191 

Hydraulic    
Steam    

51 

1,96 

1,17 
1,06 

1,97 
50 

2,32 

7 

1,952 
528 

77 
1,62 

1,48 
994 

2,31 
16 

1,94 
453 

826 
1,65 

69 

1,707 

1,62 

855 

17,609 
11,  591 

Total    

2,48 

2,24 

2,48 

2,400 

2,480 

2,400 

2,48 

2,48 

2,400 

2,480 

2,400 

2,48 

29,200 

191 

Hydraulic    
Steam    

1,104 
1,37 

1,230 
1,090 

1,58 

89 

1,87 
52 

1,946 
534 

1,66 

73 

95 
1,53 

89 
1,58 

865 
1,53 

1,410 

1,07 

77 
1,62 

79 
1,68 

15,  095 
14,185 

Total    

2  48 

2,32 

2,48 

2,400 

2,480 

2,400 

2,480 

2,48 

2,400 

2,48 

2,400 

2,48 

29,280 

191 

Hydraulic    
Steam    

804 
1,67 

72 
1,512 

80 
1,67 

87 
1,52 

2,480 
0 

2,400 
0 

1,73 
74 

1,52 

95 

1,81 

58 

2,48 
0 

2,400 
0 

2,48 
0 

20,528 
8,672 

Total    

2,48 

2,24 

2,48 

2,400 

2,480 

2,400 

2,48 

2,48 

2,400 

2,48 

2,400 

2,480 

29,200 

191 

Hydraulic    
Steam    

2,48 
0 

2.24C 
0 

2,48 
0 

2.400 
0 

2,480 
0 

2,400 
0 

2,48 
0 

2,48 
0 

2,400 
0 

2,48 
0 

2,400 
0 

1,860 
62 

28,580 
620 

Total    

2,48 

2,24 

2,48 

2,400 

2,480 

2,400 

2,48 

2,48 

2,40 

2,48 

2,40 

2,48 

29,200 

191 

Hydraulic    
Steam    

2,480 
0 

2,06( 
18 

2,48 
0 

2,400 
0 

2,480 
0 

1,98 
41 

2,48 
'0 

2,480 
0 

2,400 
0 

2,18 
29 

1,89 

506 

2,165 
31 

27,488 
1,712 

Total    

2,48 

2  24 

2,48 

2,400 

2,480 

2,40 

2,48 

2,48 

2,4( 

2,48 

2,400 

2,480 

29,200 

191 

Hydraulic    
Steam    

2,  05S 

4& 

1,76 
53 

1,59 

88? 

2,40(1 
0 

2,480 
0 

1,823 
57 

1,70 

780 

89 
1,59 

86 
1,54 

1,44 
1,03 

74 
1,654 

71 

1,76 

18,471 
10,809 

Total    

2,48 

2,32 

2,48( 

2.40C 

2,480 

2,4( 

2,48 

2,48 

2,4( 

2,48 

2.40C 

2.48C 

29,280 

2  40C 

92 

36C 

8,101 

1    79 

R9S 

o 

1  55 

"  I  • 

11,339 

24Qfl 

2  40C 

2  48 

2,48 

19,440 

Hydraulic    .... 
Steam    

l,39r 
1,08, 

1,30" 
95. 

1,52 

9b 

1,831 
56 

2,237 
143 

2,11 

28 

2,07 
40 

1,80" 

67 

1,84 
55 

1,85 
62 

1,56 
83 

1,58 
89( 

21,300 
7,920 

Total    

2,48 

2,251 

2,48 

2,4<X 

2,480 

2,40i 

2,48 

2,48 

2,4<X 

2,48 

2.40C 

8 

29,  220 

%   Hydraulic 
%  Steam  

56. 
43. 

57 
42 

61 
38 

76. 
23. 

94.2 
5.8 

88. 
11. 

83. 
16. 

72. 
27. 

76. 
23. 

74. 
25. 

65. 
34. 

63. 
36. 

72.9 
27.1 

Power  Calculations. 


71 


too 

80 

60 

4O 

?0 

0 

100 
80 
60 


/6SO     CONTINUOUS       HORSE:    POWER      UNDER      6O    FEET       HEAD 
1893  J899  /900 1901  I9O2  /9O3  /9O4 I9OS 1906 1907 19O8  /909  I9IO 191  /  /9I2  /9I3  /9/4 1915  1916  1917 


\ 
I 


80 

\ 
40 

30 
0 

100 
80 

60 
40 

20 


4O 


60 


80 


100 


/65O      CONTINUOUS       HORSE      POWER     UNDER      65    FEET      HEAD 
J898  /899  J900J9O/  1902  1903  1904  /905  1906  1907  1908  1909  1910  191  /  1912  1913  1914  1915  /9I6  1917 


330O     CONTINUOUS       HORSE      POWER      UNDER      6O   FEET      HEAD 
1898  1899  1900  1901  1902  /903  1904  /905  /906  / 907 1908 1909 19/O  1911  I9IZ  J9/3  /9/4  19/5  1916  /9/7 


3300     CONTINUOUS       HORSE      POWER      UNDER       65    FEET 
1898  /899  1900  1301  1902 1903 1904-  /905 1906  I9O7  I908I9O9I9IO  1911  I9IZ  1913  1914  19(5  1916  1917 


4O 


80 


100 


60 


80 


FIGURE  100— Graphical  Comparison  of  Relative  Percentages  of  Hydraulic  and   Steam 
Power  to  Develop  1650  and  3300  Continuous  Horse  Power  at  60  and  65  Foot  Heads. 


1 72  Report   on   the   Dam   at  Austin,   Texas. 

As  a  final  graphical  comparison,  the  relative  percentages  of  hydraulic  and  steam 
power  necessary  to  develop  1650  continuous  horse  power  under  65  and  60  foot 
heads,  and  for  each  year  from  1898  to  1917,  are  shown  in  Fig.  100,  page  171. 

A  similiar  comparison  for  65  and  60  foot  heads  and  for  3300  continuous  horse 
power  is  shown  also  by  these  diagrams  (Fig.  100). 

Effect  of  Smaller  Storage. — Estimates  have  also  been  made  to  determine  the  ef- 
fect of  the  smaller  reservoir  capacity  mentioned  above,  and  it  has  been  estimated 
that  for  a  development  of  1650  horse  power,  the  smaller  storage  would  decrease  the 
hydraulic  power  about  2.07  per  cent  for  a  60-foot  head  and  about  2.37  per  cent,  for 
a  65-foot  head.  For  3300  horse  power,  the  reduction  in  storage  would  decrease  the 
hydraulic  power  about  2.89  per  cent,  for  a  60-foot  head,  and  about  3.01  per  cent,  for 
a  65-foot  head.  The  reduction  would,  therefore,  in  both  cases  be  more  favorable  to 
the  60-foot  head,  but  is  in  any  event  only  a  small  factor. 

Reduction  of  Evaporation  and  Seepage. — It  should  also  be  noted  that  the  re- 
duction of  the  crest  from  65  to  60  feet  will  not  only  reduce  the  storage  capacity,  but 
also  the  reservoir  areas.  The  reduction  of  the  reservoir  area  from  3000  to  2000 
acres  will  reduce  the  evaporation  essentially  in  proportion  to  the  reduction  in  area. 
The  reduction  in  head  will  also  decrease  to  some  extent  the  leakage  at  the  dam.  For 
these  reasons  the  estimates  above  are  believed  to  be  more  than  fair  to  the  65-foot 
head. 

Variations  in  Load. — It  should  be  noted,  in  connection  with  these  calculations, 
that  the  use  of  power  by  the  City  is  not  on  a  uniform  continuous  load,  as  would  be 
indicated  by  the  above  calculations,  but  varies  somewhat  from  month  to  month,  and 
to  a  great  degree  from  day  to  day  and  from  hour  to  hour.  The  hourly  and  daily 
variations  can,  however,  be  equalized  by  the  reservoir  without  modifying  the  above 
calculations.  The  actual  monthly  variations  which  will  occur  may  modify  some- 
what the  proportion  and  amount  of  steam  and  hydraulic  power  that  would  be  avail- 
ble  to  supply  the  demand.  These  modifications,  however,  would  not  seriously  affect 
the  comparison  of  the  relative  values  of  60  and  65  foot  heads,  and  the  above  esti- 
mates are  therefore  believed  to  be  approximately  correct. 


APPENDIX  7 

CREST  GATES  FOR  THE  AUSTIN  DAM 

Conditions  of  Installation. — In  the  flood  of  September,  1915,  the  vast  network  of 
drift  that  accumulated  behind  the  Austin  dam  is  said  to  have  occupied  an  area  of 
several  acres,  and  the  writer  is  advised  that  it  came  down  the  river  near  the  crest  of 
the  flood  matted  together  and  in  almost  a  single  extensive  raft.  It  had  apparently 
collected  for  a  considerable  period  in  the  shallow  waters  above  the  pond,  or  possibly 
in  the  still  waters  of  the  pond  itself,  where  there  was  insufficient  current  and  depth 
for  flotation.  From  these  points  the  flood  waters  dislodged  it  and  carried  it  down- 
stream until  it  was  stopped  by  the  gate  piers  of  the  dam.  This  great  mass  of  drift 
apparently  accumulated  to  a  thickness  of  20  feet  or  more  next  to  the  dam  where  the 
pressure  of  the  water  from  behind  and  the  resistance  of  the  dam  in  front,  forced 
submergence  of  the  front  of  the  raft  and  the  piling  up  of  the  material  behind.  See 
Figs.  10  and  11,  page  26  and  Figs.  78,  79  and  80,  pages  137  and  138. 

The  writer  believes  that  it  is  impracticable  to  construct  any  crest  gates  in  the 
Austin  dam  which  will  pass  without  great  difficulty  such  great  masses  of  drift  as 
came  down  with  the  flood  of  September,  1915 ;  and  that  no  gates  can  be  made  to  work 
successfully  without  the  use  of  drift  barriers  at  the  upper  limits  of  the  reservoir. 
Such  barriers  would  be  expensive  to  construct  and  maintain,  and  without  such  bar- 
riers there  will  be  a  large  expense  at  each  great  flood  for  handling  drift.  The  con- 
struction and  maintenance  of  gates  will  therefore  be  an  expensive  matter  irrespec- 
tive of  their  design. 

From  the  information  available  it  appears  that  the  destruction  of  the  gates 
which  were  installed  on  the  dam  was  due  not  so  much  to  drift  as  to  light  construc- 
tion, stiffness  of  action  on  account  of  methods  of  stanching,  and  to  the  inertia  result- 
ing from  the  opening  of  the  gates  at  considerable  stages  of  flow. 

To  secure  adequate  service,  even  with  much  less  drift,  stronger  gates  are  needed 
to  stand  the  great  flood  flows  and  the  debris.  Such  gates  must  also  be  longer : 

1st.  To  eliminate  as  many  of  the  gate  piers  as  practicable  in  order  to  pass 
drift  even  in  small  quantities. 

2d.  To  eliminate  leakage  by  the  reduction  of  the  number  of  free  gate  ends 
and  to  make  the  friction  due  to  stanching  only  a  minor  factor  in  the  operation  of 
the  gates. 

To  accomplish  these  objects,  it  will  be  necessary  to  remove  at  least  two  out  of 
three  piers  from  the  new  portion  of  the  dam.  It  will  probably  be  safe  to  retain 


1 74  Report  on  the  Dam  at  Austin,   Texas. 

the  piers  on  the  old  portion  of  the  dam  as  originally  installed,  if  satisfactory  gates 
are  installed  on  the  new  section  which  can  be  opened  in  advance  of  the  removal  of 
the  crest  gates  or  flashboards  on  the  old  section  and  thus  create  a  strong  and  steady 
current  toward  the  new  section  to  assure  the  floating  of  the  drift  to  the  larger 
gates.  Such  an  arrangement  is  suggested  simply  as  a  matter  of  economy  as  it 
would  otherwise  be  preferable  to  use  similar  gates  on  all  portions  of  the  dam. 

Types  of  Gates  Available. — Divers  appurtenances  are  applicable  under  different 
conditions  to  temporarily  raise  the  water  above  the  crest  of  the  dam  during  the  low 
water  stage  and  which  are  removable  in  one  way  or  another  during  floods,  in  order 
to  permit  free  flow.  Flashboards  attached  to  permanent  piers  or  to  temporary  ad- 
justable standards  and  vertical  needles,  held  by  crest  blocks  and  an  upper  support, 
are  the  simplest  forms  used  for  such.  They  must  be  placed  and  removed  wholly  or 
in  part  by  hand,  during  flood  periods  and  in  general  are  applicable  only  where  flood 
periods  are  not  too  frequent,  are  fairly  definite  in  time  of  occurrence,  and  can  be 
foreseen  sufficiently  in  advance  to  admit  of  the  work  of  removal  of  the  boards  or 
needles.  Such  types  are  hardly  applicable  for  use  on  the  entire  crest  under  the  con- 
ditions on  the  Colorado  where  floods  may  occur  at  almost  any  period  of  the  year,  and 
where  they  commonly  occur  suddenly  and  without  sufficient  warning  to  admit  of 
proper  preparations.  Such  devices  might  be  used  to  advantage  on  a  part  of  the  dam. 

If  gates  are  used  at  all  under  the  conditions  at  the  Austin  dam  some  form  of 
permanent  adjustable  apparatus  must  be  used,  at  least  for  the  new  section  of  the 
crest,  which  will  either  be  automatic  in  action  or  which  can  be  readily  and  promptly 
removed  and  replaced  at  the  approach  and  after  the  occurrence  of  floods. 

Of  the  automatic  types,  the  type  already  installed  by  the  City  Water  Power 
Company  (see  page  175)  cannot  be  successfully  used  as  it  depends  on  bearings  which 
can  be  successfully  applied  only  to  short  spans,  and  the  gate  even  when  open  ser- 
iously obstructs  the  water  and  assures  either  the  clogging  of  the  passage  with  drift  or 
its  own  destruction.  Two  other  forms  of  automatic  gates  have  been  successfully 
used  in  Europe.  Two  types  designed  by  the  Stauwerke  Company  of  Zurich  are 
shown  on  page  176.  Of  these  gates,  Fig.  103,  called  the  Stauwerke  automatic  gate, 
has  been  used  to  some  extent  in  this  country.  One  installation  has  recently  been 
placed  at  the  Wissota  dam  of  the  Wisconsin-Minnesota  Power  Company  on  the 
Chippewa  River  in  Wisconsin.  Fig.  104  (page  176)  called  the  drum  gate,  is  applica- 
ble to  rivers  where  ice  troubles  are  not  serious,  and  has  also  been  used  in  slightly  dif- 
ferent forms  on  various  dams  in  the  United  States.  Both  of  these  types  have  the 
advantage  of  being  directly  hinged  to  the  crest  of  the  dam,  thus  giving  numerous 
points  of  support,  greater  strength  and  hence  the  possibility  of  greater  gate  length. 
They  also  possess  an  additional  advantage  over  the  gate  which  has  been  tried  at  the 
Austin  dam  in  that  they  fold  down  on  the  crest  of  the  dam  and  present  no  obstruction 
to  the  free  passage  of  flood  waters  and  of  drift.  On  account  of  the  details  of  the  de- 
signs, these  gates  would  be  limited  to  a  ten-foot  height  at  the  Austin  dam.  The  writer 


Crest  Gates. 


175 


has  not  sufficient  confidence  in  the  drum  gate  to  feel  safe  in  suggesting  its  use  for  the 
long  spans  required  on  the  Austin  dam.  Its  cost  would  appear  to  be  somewhat  less 
than  that  of  the  other  types  of  gates  on  which  estimates  have  been  made. 

Non-automatic  gates  which  have  to  be  raised  or  lowered  by  motors  or  by  hand 
power  are  more  numerous  and  more  positive  in  action  but  are  subject  to  the  disad- 
vantage that  they  need  attention  when  used.  Of  such  gates  there  are  numerous  de- 


Top  o< /?o, 


_.  <*fe«  WLotPorxt IWff 

e/*s  noo 


j 


te 3  IS'O'tiiyh,  !&•(,  '  fono 


Cfoseat 


WL  f/er.  I5to 


FIQUBE  101 — Fifteen-Foot  Automatic  Gates  used  on  the  Austin  Dam. 


Top  of  fat/  E/ev  l7kO 


FIGURE  102 — Six-Foot  Automatic  Gates  used  on 
the  Austin  Dam. 

signs  among  which  may  be  mentioned  Stoney  gates,  rolling  gates  and  tainter  gates. 
There  are  numerous  other  crest  gates  such  as  hydraulic  drum  and  hydraulic  sector 
gates  which  are  not  considered  applicable  to  the  conditions  at  Austin  and  are  not 
here  discussed. 

The  Stoney  gates  are  not  believed  to  be  applicable  to  the  conditions  at  the  Austin 
dam  on  account  of  the  width  of  span  required,  the  great  pressure  to  be  carried  by 
the  gates,  the  long  lines  where  leakage  must  be  effectively  prevented,  the  consider- 
able friction  of  operation  and  the  resulting  expense  involved. 

Rolling  gates  (Fig.  105,  page  177)  have  been  widely  used  in  Europe,  and  a  number 
of  these  gates  have  also  been  installed  in  this  country.  These  gates  are  supported 


76 


Report   on   the  Darn   at  Austin,   Texas. 


only  at  the  ends,  requiring  somewhat  massive  machinery  for  their  operation  and 
heavy  abutments  to  assure  their  stability  and  successful  operation.  They  have 
sometimes  leaked  badly  when  not  properly  designed  or  constructed. 

The  tainter  gates  (Fig.  106)  are  also  supported  at  the  ends  and  do  not  differ 
greatly  in  weight  from  the  roller  gates.  They  have  been  widely  used  in  this  country 
but  usually  for  shorter  spans  than  that  required  at  Austin. 


9  Gates    SS  Ft.  Long 
f  '  Piers 


FIGURE  103 — Stauwerke  Automatic  Gate. 


5 Gates  WO  Ft  Long 
4-  5 'Piers  and  2-s'End  Piers 


FIGURE  104 — Stauwerke  Drum  Gate. 

In  the  consideration  of  the  problem  of  the  Austin  dam,  four  conditions,  so  far  as 
the  crest  is  concerned,  may  be  considered: 

1st.  The  use  of  the  dam  crest  as  at  present  constructed  without  gates. 

2d.  The  use  of  the  dam  crest  as  constructed  with  gates  raising  the  water 
to  elevation  165  as  provided  in  the  Johnson  franchise. 

3d.  The  use  of  5-foot  gates  with  the  crest  of  the  reinforced  concrete  struc- 
ture raised  to  160. 

4th.  The  use  of  the  dam  without  gates,  and  with  the  crest  of  the  new  section 
raised  to  elevation  160. 


Crest  Gates. 


77 


First. — The  use  of  the  dam  crest  at  its  present  elevation  without  gates  could 
be  considered  only  as  a  temporary  expedient  as  the  head  and  the  available  storage, 
on  account  of  the  low  crest  elevation  of  the  new  section  (elevation  151)  would  be  so 
small  that  the  minimum  power  could  not  be  maintained  without  an  undue  use  of 
steam. 


9  Gafef    SI  rf  Lory 
/»' Pitrt. 


FIGURE  105 — Rolling  Gate. 


9  Gaffs     55  ff  L 
S  '  Piers 


FIQUBE  106 — Tainter  Gate. 

Second. — The  use  of  the  dam  as  already  constructed  with  gates  of  a  similar 

height  to  those  already  used  but  with  an  increased  length,  as  previously  discussed. 
In  each  case  flashboards  are  considered  for  use  over  the  old  sections  of  the  dam 

and  gates  over  the  new  section.     The  expense  of  construction  involved,  including 

the  flashboards,  is  estimated  as  follows : 

10'  Stauwerke  Automatic  Gates  and  Flashboards    $420,500 

15'  Boiler  Gates  and  Flashboards  597,400 

15'  Tainter  Gates  and  Flashboards  363,000 

The  records  of  the  last  twenty  years  show  that  the  flashboards  when  used  for 

only  half  of  the  dam  would  not  have  to  be  removed  more  than  once  in  two  years, 


1 78  Report   on  the  Dam   at  Austin,   Texas. 

and  if  washed  out  at  every  great  flood  the  expense  of  their  replacement  would  be 
small. 

Third. — The  cost  of  gates  might  be  reduced  somewhat  if  the  crest  of  the  new 
portion  of  the  dam  is  raised  to  the  height  of  the  old  crest.  This  would  raise  the  water 
level  above  the  dam  higher  at  extreme  flood,  but  as  the  old  dam  section  is  unsafe  in 
its  present  condition  and  must  be  strengthened  in  any  event,  this  would  not  therefore 
be  considered  as  an  added  expense  to  the  lower  gates.  The  cost  of  raising  the  crest 
of  the  reinforced  concrete  dam  (which  is  estimated  at  $53,000)  must  however  be  con- 
sidered as  a  part  of  the  cost  of  five-foot  gates  in  comparison  with  the  cost  of  gates 
for  the  dam  with  its  present  crest  elevation.  If  the  dam  crest  is  raised  and  five- 
foot  gates  are  used,  flashboards  could  not  be  used  successfully  as  they  would  go  out 
with  every  considerable  flood ;  and  in  the  narrow  openings  over  the  old  section,  tainter 
gates  could  be  used  to  advantage.  The  estimates  for  five-foot  gates,  56  feet  wide, 
over  the  new  portions  of  the  dam  and  for  tainter  gates  of  18-foot  width  over  the  old 
dam,  are  as  follows : 

With  Raised 
Gates  Only  Crest 

5'  Stauwerke  and  5'  Tainter  Gates $390,200  $443,200 

5'  Boiling  and  5'  Tainter  Gates 420,300  473,000 

5'  Tainter  Gates 329,000  382,000 

It  should  be  noted  that  a  considerable  element  of  the  apparently  high  cost  of  all  of 
these  different  types  of  gates  is  due  to  the  necessity  of  constructing  new  and  heavier 
piers  from  the  foundation  to  and  in  some  cases  above  the  top  of  the  present  reinforced 
concrete  piers;  also  of  constructing  a  new  overhead  bridge  in  order  to  permit  ac- 
cess to  the  gates  for  maintenance  and  repairs  under  all  conditions  of  flow. 

Fourth. — The  cost  of  raising  the  concrete  crest  of  the  new  dam  to  elevation  160 
is  estimated  at  $53,000.  This  would  reestablish  the  crest  elevation  maintained  from 
1893  to  1900  and,  as  shown  in  Appendix  6,  will  give  the  most  economical  develop- 
ment. 

The  writer  is  firmly  of  the  belief  that  the  increased  power  obtainable  at  elevation 
165  does  not  warrant  the  extra  expense,  the  additional  leakage  and  the  additional  eva- 
poration which  will  result  from  the  higher  head. 


APPENDIX  8 

BETTERMENTS  REQUIRED  FOR  THE  SAFETY  OF  THE  AUSTIN  DAM 

In  the  design  of  engineering  works  an  exact  line  between  safety  and  danger 
cannot  be  drawn  with  any  great  degree  of  accuracy.  The  conditions  assumed  in  the 
design  of  any  structure  will  seldom  be  found  to  obtain  exactly.  The  exact  strength 
of  the  materials  used  cannot  be  known.  All  of  these  uncertainties  must  be  provided 
for  by  an  allowance  of  extra  strength  to  more  than  make  up  for  the  uncertainties 
which  may  obtain.  Of  all  engineering  structures  the  conditions  which  surround  the 
average  dam  are  perhaps  the  most  uncertain.  The  character  of  the  foundation  must 
be  judged  from  surface  indications,  and  at  best  from  a  limited  number  of  borings. 

With  all  the  work  that  has  been  done  at  the  site  of  the  Austin  dam,  there  is  still 
much  uncertainty  as  to  the  exact  physical  condition  of  the  underlying  strata  and  as 
to  the  exact  extent  of  the  remedies  that  must  be  applied  to  make  the  dam  safe.  Un- 
certainties also  exist  as  to  the  maximum  river  flow.  The  highest  flood  that  may  ob- 
tain in  time  to  come  can  be  estimated  only  on  the  basis  of  what  has  occurred  in  the 
past,  and  the  conditions  of  silt  and  drift  which  may  obtain  in  the  future  must  be 
judged  in  the  same  way.  The  dam  failed  in  1900  because  the  conditions  were  not 
correctly  judged  in  1890-93.  Leaks  appeared  under  the  base  of  the  dam  in  1915 
and  the  crest  gates  proved  a  failure  because  the  precautions  taken  in  1911-14  were 
not  sufficient  for  their  purpose.  Just  what  was  necessary  in  either  case  to  have  made 
the  structure  safe  without  any  unnecessary  expenditure  cannot  be  told. 

The  only  safe  basis  of  engineering  design  is  to  build  a  structure  so  safe  that 
there  is  no  reasonable  chance  remaining  for  its  destruction.  It  is  also  necessary  to 
remember  that  neither  the  City  nor  the  private  parties  who  are  interested  in  the  Aus- 
tin dam  have  money  to  waste  and  it  is  essential  that  nothing  shall  be  expended  in 
useless  work. 

In  considering  the  betterments  that  are  justifiable  at  the  Austin  dam  it  is  recog- 
nized that  there  is  opportunity  for  a  wide  difference  in  the  opinion  of  engineers,  ac- 
cording to  their  experience  and  mental  attitudes,  as  to  the  extent  of  the  improve- 
ments necessary  for  safety;  and  preliminary  to  the  recommendations  herein  con- 
tained the  writer  desires  to  say  that  these  matters  have  been  carefully  weighted, 
and  the  betterments  advised  are  those  which  he  would  feel  it  necessary  to  carry  out 
were  he  the  owner  of  the  dam  and  were  it  necessary  for  him  to  plan  its  proper  re- 
habilitation for  continued  use. 

The  writer  agrees  with  Messrs.  Davis,  Hill  and  T.  U.  Taylor  that  the  dam 
should  not  have  been  reconstructed  on  the  present  site;  that  the  conditions  made 
manifest  by  the  first  failure  and  by  the  various  geological  and  engineering  investi- 


180  Report   on  the  Dam   at  Austin,   Texas. 

gallons  which  have  been  described,  showed  conclusively  the  dangerous  character  of 
the  foundation  and  that  it  was  exceedingly  difficult,  at  reasonable  expense,  to  build 
a  structure  at  this  site  the  safety  of  which  could  be  positively  assured.  However, 
the  City  is  confronted  with  facts,  not  theories.  The  site  has  been  accepted  by  the 
City,  the  dam  has  been  reconstructed,  a  large  investment  is  involved,  and  it  remains 
to  consider  the  means  necessary  to  render  the  structure  as  safe  as  it  can  be  made 
within  practicable  limits  of  expense. 

Foundation. — The  writer  is  of  the  opinion  that  it  is  practically  impossible  to 
comply  with  the  requirements  of  the  specifications  and  find  six  feet  (or  even  four 
feet)  of  solid  rock  in  the  east  section  of  the  dam  on  which  to  build  this  structure.  He 
is  also  of  the  opinion  that  even  if  such  thickness  of  rock  were  available,  it  would 
afford  no  assurance  against  serious  deep  underflow.  It  is  therefore  essential  to  take 
such  precautions  as  are  financially  practicable  toward  improving  these  conditions 
and  rendering  the  substrata  practically  impervious. 

Grouting  as  a  Protection  Against  Underflow. — The  history  of  the  process  of 
grouting  dam  foundations  has  not  demonstrated  its  reliability  as  a  positive  method 
of  preventing  underflow.  Grouting  has  usually  been  applied  only  as  an  extra  pre- 
caution after  other  practicable  and  more  positive  methods  have  been  employed.  The 
writer  considers  the  conditions  of  the  strata  at  the  dam  site  as  fairly  suitable  for  the 
application  of  grouting  methods,  and  believes  grout  should  be  utilized  for  further 
betterments  of  the  conditions. 

Foundation  Betterments  Recommended. — The  writer  believes  that  a  cutoff  wall 
about  30  feet  below  the  bottom  of  the  river  and  across  the  entire  section  of  the  new 
dam  at  its  upstream  face  is  the  first  essential  for  safety.  Such  a  cutoff  wall  should 
completely  fill  the  rock  trench  in  which  it  is  built,  so  that  the  excavation  of  the  strata 
will  not  afford  a  means  of  access  of  water  to  the  upstream  rock  face  of  the  excava- 
tion. He  believes  that  the  safety  from  underflow  should  be  still  further  assured  by 
thorough  grouting  in  holes  50  to  60  feet  in  depth,  drilled  not  more  than  four  feet 
apart  and  in  at  least  two  rows  across  the  entire  width  of  the  river.  The  depth,  spac- 
ing and  number  of  rows  of  holes  should  be  determined  by  the  condition  found  during 
the  execution  of  the  work. 

It  will  probably  be  desirable  and  perhaps  essential  to  complete  the  work  of 
grouting  before  the  excavation  for  the  cutoff  wall  is  attempted,  as  otherwise  fissures 
in  the  cutoff  trench  might  make  it  impossible  to  construct  successfully  the  cutoff 
wall.  By  first  grouting  the  strata,  the  excavation  for  the  cutoff  wall  will  be  less  ex- 
pensive and  the  excavation  will  also  demonstrate  the  effectiveness  of  the  grouting 
work.  If  the  grouting  is  found  to  be  thoroughly  effective,  it  may  be  feasible  to  re- 
duce the  depth  of  the  cutoff  wall  to  15  or  20  feet  and  may  make  it  unnecessary  to  con- 
struct a  cutoff  wall  behind  the  old  section.  If  the  grouting  is  not  fairly  effective,  a 
cutoff  wall  at  least  ten  feet  in  depth  should  also  be  constructed  immediately  behind 
the  old  section. 


Recommended  Betterments  181 

Stopping  Leaks  in  Panels  4  and  6. — The  exact  details  of  the  methods  necessary 
for  stopping  the  leaks  in  Panels  4  and  6  cannot  be  foretold  accurately  without  a  de- 
tailed examination,  which  the  writer  has  n0t  been  able  to  make  and  which  cannot  well 
be  undertaken  until  the  work  of  rehabilitation  is  begun.  The  conditions  as  known 
are  described  on  pages  94  and  110.  When  the  water  was  lowered  above  the 
dam,  the  leaks  stopped  flowing  after  the  water  had  reached  a  certain  elevation  above 
the  opening  through  which  the  leaks  appeared.  Before  grouting  above  the  dam  it 
will  be  necessary  to  construct  cofferdams  around  these  leaks  to  such  a  height  that  the 
water  will  rise  and  become  stationary  so  that  there  will  be  no  current  through  the 
rock  fissures.  With  this  accomplished  it  may  be  possible  that  the  deep  grouting  which 
has  been  recommended  to  be  done  above  the  dam  will  find  its  way  into  the  cavities 
and  fissures  through  which  these  leaks  occur,  and  effectively  close  them.  If  not,  the 
rock  in  the  immediate  vicinity  of  the  cavities  must  be  cleared  of  debris  and  grout 
forced  deep  into  the  fissures.  The  leaks  cannot  be  stopped  successfully  and  perman- 
ently with  a  surface  deposit  of  concrete  or  by  grouting  in  their  shallow  upper  por- 
tion but  the  grout  must  be  forced  into  these  fissures  for  15  or  20  feet  in  depth. 

It  may  be  essential  to  drill  one  or  more  holes  into  the  strata  through  or  immedi- 
ately adjoining  the  fissures,  and  force  the  grout  into  the  strata  from  a  depth  of  15  feet 
or  more  below  the  surface,  until  it  finally  fills  these  fissures  to  the  surface  of  the  rock. 
If  the  filling  cannot  be  properly  made  by  such  means,  a  pipe  may  be  placed  as  deep 
as  practicable  in  the  strata  adjacent  to  the  fissures  with  its  top  rising  above  the  sur- 
face of  the  water,  and  a  bed  of  concrete  two  or  more  feet  in  thickness  deposited 
above  the  fissure  to  afford  a  resistance  to  the  surface  outflow  of  the  grout,  after 
which  grout  may  be  pumped  into  the  fissure  through  the  pipe,  filling  it  to  a  consider- 
able depth  through  the  surface  resistance  afforded  by  the  concrete  bed.  It  is  under- 
stood that  the  opening  in  Panel  No.  6  is  of  considerable  size,  and  a  large  amount  of 
grout  will  probably  be  required  for  the  complete  stopping  of  this  fissure. 

In  Panel  No.  4  it  is  understood  that  no  examination  has  yet  been  made  and  that 
the  leak  is  comparatively  small.  In  this  case,  unless  the  fissure  is  closed  by  the 
grouting  above  the  dam,  it  will  become  necessary  to  drill  into  the  strata  in  order  to 
give  free  access  of  the  grout  to  the  underlying  fissures.  The  exact  details  to  be  em- 
ployed can  best  be  determined  at  the  time  the  work  is  undertaken.  After  the  suc- 
cessful stopping  of  these  leaks,  it  will  probably  be  desirable  to  lay  a  reinforced  con- 
crete floor  in  the  upper  portion  of  these  panels  as  an  additional  precaution  against 
further  trouble. 

Effectiveness  of  Protection. — With  such  precautions,  it  is  believed  that  destruc- 
tive underflow  can  be  prevented,  although  no  one  can  positively  say  that  weaknesses 
along  the  fault  lines  which  may  ultimately  prove  troublesome  may  not  develop  even 
below  the  depths  mentioned.  The  fact  that  the  dam  stood  from  1893  to  1900  without 
such  developments  is,  however,  an  assurance  of  safety.  It  is  believed  that  with 


182  Report  on  the  Dam  at  Austin,   Texas. 

proper  care  the  risk  of  further  trouble  will  be  small,  and  considering  the  importance  of 
the  project  and  the  investment  already  incurred,  the  expense  involved  is  warranted. 

Improvements  of  Conditions  Below  the  Toe  of  the  Dam. — The  conditions  below 
the  toe  of  the  new  section  have  already  been  described  (see  pages  98  to  106).  These 
conditions  are  sources  of  danger  to  the  new  structure  and  will  become  worse  with 
every  large  flood.  One  of  the  most  necessary  betterments  will  consist  of  filling  up 
this  depression  and  constructing  an  apron  of  sufficient  thickness  and  strength  to 
both  protect  the  bottom  and  afford  a  substantial  abutment  against  which  the  cross 
walls  of  the  new  structure  will  rest.  The  top  of  the  apron  should  reach  above  the 
foundations  of  the  cross  walls  at  the  toe  of  the  dam  and  be  so  constructed  as  to  give 
them  an  ample  bearing.  It  is  not  considered  necessary  to  bring  the  top  of  this  apron 
to  a  horizontal  plane  above  the  most  shallow  cross  wall  but  it  should  have  a  substan- 
tial thickness  over  the  entire  section  of  the  trough  between  the  toe  of  the  new  struc- 
ture and  the  rock  ledge  below.  This  apron  should  be  constructed  of  cyclopean  con- 
crete in  which  should  be  imbedded  a  considerable  amount  of  large  rock  from  the  de- 
bris which  is  now  piled  between  the  toe  of  the  dam  and  the  tail  race.  In  this  way 
the  construction  may  be  cheapened  and  much  of  the  debris  which  is  liable  at  any  time 
to  be  washed  into  the  tail  race  will  be  removed.  Weep  holes  should  be  provided 
in  this  apron  to  eliminate  upward  pressure.  With  such  construction  properly  plan- 
ned the  new  structure  may  be  regarded  as  reasonably  safe. 

While  the  rock  bottom  of  the  river  below  the  structure  of  the  old  dam  has  not 
been  seriously  eroded,  if  at  all,  it  is  believed  necessary  to  protect  this  rock  by  a  layer 
of  concrete  about  50  feet  in  width,  which  should  start  at  elevation  100  at  the  toe  of  the 
dam  but  can  be  decreased  to  about  2  feet  in  thickness  at  its  outer  limits.  Under 
this  structure  drains  and  weep  holes  should  also  be  provided  to  eliminate  upward 
pressure. 

Crest  Gates. — The  difficulty  of  maintaining  any  form  of  crest  gates  has  already 
been  discussed,  and  the  expense  involved  by  the  erection  and  maintenance  of  any 
gates  which  might  prove  reasonably  satisfactory  has  been  shown  in  Appendix  7. 

In  Appendix  6  it  has  been  demonstrated  that  the  amount  of  extra  power  which 
can  be  secured  by  maintaining  the  maximum  surface  of  the  water  at  elevation  165 
is  not  of  sufficient  value  to  warrant  the  expense  involved.  It  is  therefore  recom- 
mended that  no  crest  gates  be  used  but  that  the  gate  piers  be  entirely  removed  from 
the  dam  and  the  crest  of  the  new  structure  be  raised  to  elevation  160.  The  amount 
of  hydraulic  power  thus  lost  can,  it  is  believed,  be  more  cheaply  recovered  by  a  sys- 
tematic attempt  to  reduce  the  seepage  into  the  rock  and  around  the  dam  on  both 
sides  of  the  river. 

Reduction  in  Seepage  Around  the  Dam. — It  is  believed  to  be  desirable  to  reduce 
the  seepage  immediately  around  the  west  end  of  the  dam  by  grouting  the  natural  rock 
ledge  both  immediately  above  and  below  the  west  end  of  the  dam.  On  the  east  side 
of  the  river  opportunities  for  saving  a  much  larger  quantity  of  water  are  apparent. 


Improvements  to  Old  Dam  Section. 


183 


The  nature  of  the  work  to  be  done  can  be  only  partially  outlined,  but  it  is  believed 
that  the  most  pervious  strata  are  near  the  elevation  of  the  old  flood  plane  above  the 
dam  and  that  these  strata  should  be  exposed  by  a  comparatively  shallow  trench  along 
the  face  of  the  bluff,  and  the  seepage  stopped  by  facing  the  pervious  strata  with  con- 
crete and  perhaps  in  places  by  grouting.  While  the  results  which  can  be  attained  by 
such  work  cannot  accurately  be  foretold,  it  is  believed  that  the  seepage  into  these 
strata  may  be  reduced  perhaps  50  per  cent,  or  more  at  an  expense  which  will  be  more 
than  justified  by  the  results  obtained. 

Improvements  to  the  Old  Dam  Section. — It  is  quite  evident  from  the  analysis 
and  discussion  of  the  old  dam  (see  pages  124  to  130)  that  it  has  too  light  a  section  to 


W.J.&.  174.0-^). 


\M/afc//»  7ft/r<^Sj          ft-  ^^y^\ 


7O.O' 


FIGURE  107 — Recommended  Improvement  to  Old  Dam  Section. 

be  safely  stable  with  its  pervious  foundation,  the  silt  pressure  which  must  be  anti- 
cipated, and  the  conditions  of  flood  flow,  even  though  the  crest  remain  at  elevation 
160.  Its  section  is  also  so  narrow  that  the  under  surface  of  the  flood  waters  flowing 
over  it  must  leave  the  surface,  thus  creating  a  partial  vacuum  and  adding  to  the 
pressure  head  above  the  dam.  Were  the  channel  clear  of  the  new  structure,  it  might 
be  desirable  to  strengthen  the  old  section  by  addition  to  the  upstream  face ;  but  under 
the  condition  it  seems  desirable  and  less  expensive  to  improve  its  stability  and  sec- 
tion by  the  addition  of  concrete  on  the  downstream  side,  as  shown  in  Fig.  107.  It  will 
also  be  necessary  to  seal  the  base  and  fill  the  voids  in  the  structure  itself  by  thorough 
grouting  which,  together  with  the  foundation  grouting  previously  advised,  may  safely 
be  assumed  to  decrease  the  upward  pressure  in  the  foundation  to  about  one-half  of 


184  Report  on  the  Dam  at  Austin,   Texas. 

the  pressure  due  to  the  head.  The  addition  to  the  face  and  the  thickening  of  the  toe, 
possibly  with  some  heavy  reinforcing  at  that  point,  may  be  assumed  to  so  extend  the 
effective  width  of  base  as  to  throw  the  resultant  pressure  with  high  silt  and  flood  flow 
within  the  middle  third  of  the  structure.  These  improvements,  together  with  the 
extension  of  the  apron,  elsewhere  recommended,  will  so  increase  the  stability  of  the 
old  structure  as  to  render  it  permanently  safe. 

Tail  Race. — The  tail  race  is  seriously  throttled  by  the  debris  brought  in  by  the 
flood  of  September,  1915.  In  order  to  maintain  this  tailrace  it  is  necessary  not  only 
to  clean  out  the  material  which  has  been  washed  in,  but  to  remove  the  piles  of  debris 
between  the  tailrace  and  the  toe  of  the  dam  which  is  the  source  of  the  trouble.  Much 
of  the  heavy  rock  in  this  mass  can  be  used  in  the  cyclopean  concrete  of  which  the 
apron  in  front  of  the  dam  should  be  built.  The  balance  should  be  removed  across 
the  tailrace  to  the  land  side  and  deposited  on  the  shore  where  it  will  create  no  fur- 
ther trouble. 

The  writer  has  not  seen  the  tailrace  in  use,  but  is  under  the  impression  that  it 
has  not  been  excavated  deep  enough  to  properly  fulfill  its  functions.  The  rim  of  rock 
immediately  adjoining  the  draft  tubes  should  be  so  excavated  that  the  water  will  have 
a  free  delivery. 

Dr.  A.  C.  Scott,  in  his  letter  to  Mayor  Wooldridge,  dated  March  31,  1915  (see 
Appendix  10),  states  that  it  is  essential  to  deepen  the  tailrace  approximately  three 
feet.  In  its  congested  condition,  the  writer  had  no  opportunity  to  examine  this  race- 
way in  detail,  and  it  is  possible  that  with  the  removal  of  the  rubbish  between  the  race- 
way and  the  dam,  a  sufficient  opening  will  be  available  for  the  free  discharge  of  the 
water.  In  any  event,  the  tailrace  should  be  so  deepened  as  to  maintain  a  velo- 
city of  discharge  of  not  to  exceed  three  feet  per  second.  If  this  is  done,  and  the  de- 
bris removed,  there  is  no  apparent  reason  for  requiring  the  construction  of  a  con- 
crete raceway  nor  a  concrete  wall  north  of  the  raceway  as  required  by  the  specifica- 
tions, except  to  protect  the  draft  tubes. 

Deflecting  Wall. — The  north  draft  tube  was  damaged  by  drift,  probably  in  the 
flood  of  September,  1915 ;  and  such  damage  is  very  likely  to  recur  with  any  flood  ac- 
companied by  drift.  On  account  of  the  exposed  position  of  these  draft  tubes  it  is  de- 
sirable to  construct  a  deflecting  wall  which  should  begin  essentially  at  the  north  line 
of  the  present  building  with  its  top  somewhat  above  the  top  of  the  draft  tubes  and 
extend  in  a  diagonal  downstream  direction  for  about  40  feet.  The  end  of  the  wall 
should  be  10  or  12  feet  above  low  water,  and  the  top  of  the  wall  should  slope  or  may 
be  stepped  upward  to  the  power  house.  This  wall  should  be  of  reinforced  concrete, 
well  bonded  into  good  rock  foundation  and  into  the  masonry  of  the  power  house  foun- 
dations, and  should  have  a  width  of  not  less  than  2  feet  at  the  top  and  8  feet  at  the 
bottom. 

Head  Gates. — The  racks  at  the  head  gates  have  been  discussed  (see  page  140)  and 
it  has  been  noted  that  the  openings  between  these  racks  are  too  small  for  the  practi- 


Recommended  Betterments.  185 

cal  operation  of  the  turbine  units.  These  racks  should  be  taken  down  and  more  than 
one-half  of  the  rack  bars  removed,  leaving  the  free  opening  between  adjacent  bars 
about  ll/2"-  It  will  also  be  desirable  to  examine  the  rack  supports  and  see  that  they  are 
sufficiently  strong  to  sustain  the  racks,  should  the  racks  become  sealed  by  leaves  and 
drift  and  the  water  be  drawn  away  from  below  them,  leaving  the  entire  head  to  be 
sustained  by  the  strength  of  the  racks  and  their  supports. 

Passageway  in  the  Dam. — As  has  been  noted,  the  passageway  in  the  dam  con- 
sists of  a  wooden  walk  sustained  on  the  cross  walls  of  the  dam.  This  is  sagging  badly 
and  Will  have  to  be  replaced  at  an  early  date.  A  substantial  reinforced  concrete 
walk  should  be  built  in  place  of  the  wooden  structure  and  the  railing  should  be  se- 
curely anchored  thereto.  The  railing  should  be  thoroughly  cleaned  and  painted  with 
some  preservative  which  will  prevent  further  deterioration. 

Railing. — The  railing  along  the  concrete  bridge  over  the  dam  will  be  removed 
with  the  piers  if  the  dam  is  raised  to  elevation  160  and  used  without  crest  gates,  as 
elsewhere  advised.  In  that  event,  ample  railing  will  be  available  to  protect  the  abut- 
ment and  retaining  wall  from  the  dam  to  the  power  house.  In  any  event,  such  a  rail- 
ing should  be  provided  for  the  safety  of  the  public.  All  railing  should  be  thoroughly 
cleaned  and  painted. 

Gate  Operating  Mechanism. — The  gate  operating  mechanism  is  believed  to  be 
unsatisfactory  for  a  plant  of  this  character.  It  can  however  be  utilized  for  the  pres- 
ent if  found  desirable.  It  is  recommended  that  it  ultimately  be  removed  and  proper 
gate  mechanism  substituted. 

Sluiceways. — The  sluiceway  arches  which  on  account  of  defective  design  were 
destroyed  in  1915  have  been  partially  replaced.  It  is  assumed  that  this  work  has 
been  done  on  a  safe  and  satisfactory  plan,  although  no  details  of  the  new  design  were 
available.  One  additional  arch  remains  to  be  replaced  and  it  is  understood  that 
there  are  some  of  the  arches  which  were  not  destroyed  that  have  not  been  reinforced. 
These  should  be  properly  strengthened  by  additional  concrete  and  reinforcement. 

Sluice  Gates. — The  sluice  gates  are  unsatisfactory  in  design  and  arrangement  and 
they  should  at  least  be  redesigned  and  rebuilt  so  that  the  bronze  bearings  can  be 
unquestionably  maintained.  The  position  of  the  cylinders,  submerged  in  the  reser- 
voir 50  feet  below  the  crest  of  the  dam,  is  unfortunate  and  will  probably  give  rise  in 
the  future  to  considerable  annoyance  and  expense.  Backs  should  be  provided  to  pro- 
tect the  cylinders  and  to  prevent  the  entrance  of  floating  matter  into  the  gateways. 
The  reconstruction  of  the  gates,  and  their  rearrangement  in  a  more  satisfactory 
manner,  would  involve  a  considerable  expense  and  is  not  recommended  at  the  present 
time  on  account  of  other  large  but  more  essential  expenditures  which  will  have  to  be 
made  for  the  safety  of  the  structure. 

Estimates  of  Cost  of  Betterments. — The  contingencies  of  river  construction  at 
Austin  have  been  demonstrated  by  the  misfortunes  of  the  past,  and  any  estimates  for 
betterments  must  be  made  on  a  liberal  basis.  The  work  required  above  the  dam 


1 86  Report  on  the  Dam   at  Austin,   Texas. 

will  probably  involve  making  certain  openings  through  the  reinforced  concrete  struc- 
ture to  give  vent  to  the  flood  waters,  in  addition  to  the  limited  capacity  of  the  sluice 
gates.  Even  with  such  openings  the  cofferdams  will  be  drowned  out  with  every  con- 
siderable rise  and  any  work  done  above  the  dam  will  be  expensive.  In  the  estimates 
made  for  the  betterments  recommended,  liberal  amounts  have  been  allowed  in  addi- 
tion to  a  reasonable  sum  for  contingencies.  It  is  quite  probable,  with  favorable 
flow  and  weather  conditions  during  the  period  of  reconstruction,  that  a  considerable 
saving  can  be  effected  over  the  estimate  made;  but  such  conditions  cannot  be  as- 
sumed, and  it  is  believed  that  the  estimates  made  will  cover  unforeseen  foundation 
and  flood  conditions.  For  estimates  of  the  cost  of  the  betterments  see  pages  31  and 
32. 


APPENDIX  9 

COST  OF  THE  WORK  DONE  UNDER  THE  JOHNSON  CONTRACT 

It  is  obvious  that  neither  the  Engineers  of  the  City  Water  Works  Company  nor 
the  Contractor  who  undertook  the  work  at  the  Austin  dam  appreciated  the  contin- 
gencies of  river  work.  The  years  immediately  preceding  the  date  at  which  the  con- 
tracts were  made  were  the  years  of  low  flow,  but  an  examination  of  the  records  of  the 
United  States  Geological  Survey  would  have  shown  that  the  river  was  subject  to 
sudden  high  floods  and  years  of  high  flow  when  work  in  the  river  for  an  entire  season 
would  be  practically  impossible  without  large  expense.  Any  estimates  of  the  cost  of 
such  work  to  be  safe  must  anticipate  such  contingencies  and  be  large  enough  to 
cover  the  extra  expense  involved  by  the  increased  cost  of  construction  under  such 
conditions. 

The  original  cost  estimates  for  this  work  made  by  the  Engineers  of  the  City  Water 
Power  Company  and  including  $50,000  for  Contractor's  profit,  $12,000  for  royalties, 
$13,000  for  interest  during  construction,  and  $22,500  for  engineering,  was  $450,334.54. 
The  Contractor's  estimate,  including  $50,000  for  profit  and  without  royalties  or  en- 
gineering fees,  was  $453,000. 

The  writer  has  estimated  the  cost  of  the  work  done  and  in  so  doing  has  endeav- 
ored to  take  into  account  only  such  expenses  as  he  should  anticipate  under  the  con- 
ditions which  he  knows  would  be  liable  to  obtain  on  river  work  with  the  foundation 
and  flow  which  should  be  expected  to  obtain  on  the  Colorado  at  Austin.  He  has  eli- 
mated  as  far  as  practicable  his  knowledge  of  actual  cost  to  the  Contractor  by  making 
independent  estimates  without  reference  to  the  cost  data. 

Estimated  Cost  of  Reservoir. — The  reservoir  included  under  the  contract  was 
built  on  the  summit  of  the  hill  to  the  north  of  the  City  of  Austin.  Its  construction 
involved  no  serious  contingencies.  Its  estimated  cost  on  a  unit  cost  basis  is  as  fol- 
lows: 

ESTIMATE  or  COST  OF  WATER  WORKS  RESERVOIR 

Item  Quantity      Unit  Rate  Amount 

Concrete  (Thin  walls)    3,017  Cu.  Yd.  $11.00  $33,187 

Excavation 3,700  Cu.  Yd.  .50  1,850 

Steel  Reinforcing 53,700  Lbs.  .05  2,685 

4"  Triangular  Wire  Mesh  12i/2"  Gage  37,275  Lbs.  .05  1,864 

Steel  Plate  Expansion  Joint 1,850  Lbs.  .05  93 


$39,679 
Contingencies,  10  per  cent 3,971 

Total  estimate  of  cost $43,650 


188  Report   on  the  Dam   at  Austin,   Texas. 

This  estimate  may  be  compared  with  the  Contractor's  Cost  Sheet  shown  on  page 
194,  and  shows  a  close  agreement  therewith. 

Estimated  Cost  of  Rebuilding  Station,  Including  Removing  Old  Penstocks,  Plac- 
ing Neiv  Penstocks,  Rebuilding  Transmission  Lines,  etc. — This  work  is  embraced  in 
Schedule  A  of  the  contract  between  the  City  Water  Power  Company  and  the  Wm.  P. 
Carmichael  Company,  and  was  guaranteed  by  the  City  Water  Power  Company  not 
to  exceed  a  cost  of  $20,720. 


Estimates.  1 89 
The  writer's  estimate  of  the  cost  of  this  work  is  as  follows: 
ESTIMATE  OF  COST  OF  BUILDING  AND  WORK  ON  PENSTOCKS  AND  TRANSMISSION  LINE 

Item  Quantity      Unit  Rate  Amount 

Reinforced  Concrete  Floor 170  Cu.  Yd.  $12.00  $2,040 

Plain  Concrete  Floor  and  Walls  Below 

Floor  27  Cu.  Yd.  8.00  216 

Plain  Concrete  Paving  around  Surge  Pipes  29  Cu.  Yd.  8.00  232 
Brick  Walls  Abv.  Floor  Level — Sides  and 

Ends  New  Part  173  M  30.00  5,190 

Brick  Walls  below  Floor  End  Wall  and 

Wall  in  Turbine  Boom 172  M  30.00  5,160 

Windows  6  at  7'xl9'  and  2  at  6'x7' 265 

Roof  Trusses—  Wood  6,000  Ft.  BM  50.00  300 

Roofing— Slate  and  Sheathing 24  Sqs.  18.00  432 

Crane  15-Ton  Hand  49'8"  Span 1,200 

Crane  Runway  65  Ibs.  I-Beams  40  Ibs.  Rails  24,270  Lbs.  .05  1,214 
Pilaster  Alterations,  Corbels  and  Bolts  on 

13  Pilasters 195 

Plumbing,  Painting  and  Wiring 1,000 

Railings,  Gallery  and  Stairs 1,000 

Office  Room 75 

Rebuilding  Transmission  Line  15,000  Ft. 

Poles  and  Stringing  only 3,720 

Headworks  Alteration  to  Lower  Penstocks 

5'6" 500 

Relaying  Penstocks  3,065 

Concrete  Reinforcing  for  Penstocks  2,500 

Retaining  Wall  76'  long  24'  high  2'  top ...  300  Cu.  Yd.  8.00  2,400 
Relief  Pipes  32"  diam.  1  at  52',  1  at  68', 

1  at  81'  17,520  Lbs.  .07  1,226 

Draft  Tubes— Elbows  3  at  1920'  5,760  Lbs.  .07  404 

Penstock  Expansion  joints  and  elbows  . . .  8,070  Lbs.  .07  565 

Removal  Penstocks,  Floor,  Found 't  'ns,  etc.  500 

Excavation  Rock  under  Old  Power  House  375  Cu.  Yds.  2.50  940 


$34,339 
Contingencies,  10  per  cent 3,434 


Total    $37,773 


190  Report  on  the  Dam  at  Austin,   Texas. 

This  estimate  may  be  compared  with  the  Cost  Keeper's  account  of  the  Contrac- 
tor, given  on  page  195,  and  will  be  seen  to  be  about  $15,000  less  than  the  cost  there 
shown.  The  writer  is  unable  to  account  for  this  difference  as  he  has  no  reason  to 
believe  that  the  Cost  Keeper's  account  is  otherwise  than  accurate.  While  the  con- 
tingencies of  this  work  are  small  there  is  much  uncertainty  as  to  the  amount  of  work 
which  was  done,  especially  in  the  removal  of  the  old  penstocks,  the  excavation  for  and 
the  placing  of  the  new  penstocks,  and  the  work  done  below  the  floor  level  of  the  power 
house.  Legitimate  differences  in  these  items  may  possibly  account  for  much  of  the 
difference  between  the  writer's  estimate  and  the  actual  cost.  It  is  evident  from  the 
original  estimate  of  the  City  Water  Power  Company  that  much  more  work  was  done 
than  was  anticipated. 

Machinery  and  Equipment,  which  is  Schedule  B  of  the  contract  between  the  City 
Water  Power  Company  and  the  Wm.  P.  Carmichael  Company  and  was  guaranteed 
in  that  contract  not  to  exceed  a  cost  of  $79,000,  is  estimated  by  the  writer  as  follows : 

ESTIMATE  OF  COST  OF  MACHINERY  AND  EQUIPMENT — ERECTED 

Item  Price  Each      No.      Amount 

Turbines  (2400  HP)  and  Governors $9,330        3  $27,990 

Erection  13  per  cent 3,640 

Generators  1500  KVA  at  $7 : 10,500        3  31,500 

Transformers  1500  KVA  at  $2.50 3,750        3  11,250 

Switchboard 2,000        1  2,000 

Exciters  75  KW  Motor  Drive  at  $27  per  K.  W 2,000        2  4,000 

Generator  Suspension  Bearings  500        3  1,500 

Headgates  and  Hoists 300        3  900 

Backs  55,000  Ibs.  at  4c 2,200 

Pumps  and  Motors— 6  Mil.  Gallon   4,000        2  8,000 

Station  Wiring  1,000       . .  1,000 

Connections   to   Penstocks,   Draft   Tubes,  Rivetting,  Etc 300        3  900 


$94,880 
Contingencies,  5  per  cent 4,744 


Total    $99,624 

A  comparison  with  the  Contractor's  Cost  Sheet,  page  195  will  show  this  estimate 

to  be  about  $5,930  above  the  actual  cost  to  the  Contractor. 

Construction  of  the  Dam. — The  writer 's  estimate  of  the  contingencies  of  river 

work  are  partially  reflected  in  the  itemized  prices  for  unit  quantities  and  in  his  es- 


Estimates. 


191 


timate  for  the  probable  cost  of  cofferdams  and  pumping ;  otherwise  the  ordinary  con- 
tingent item  of  10  per  cent,  is  added  to  cover  this  item.    His  estimate  is  as  follows: 


ESTIMATE  OF  PROPER  COST  OF  WORK  DONE  ON  THE  AUSTIN,  TEXAS,  DAM 


Item 

Concrete 

Below  Elevation  100  Footings   

Walls,  Etc 

Above  Elevation  100 

Dam  Cross  Section  Beams,  Decks,  Etc. 

Longitudinal  Walls   

Walls  under  Overhang  

Transverse  Walls  under  Deck  

Main  Piers  

Intermediate  Piers   

Extra  in  Expansion  Panels 

Entrances  to  Dam 

Piers  on  Old  Dam 

Walkways  

Blanket  Mat  over  Old  Dam  at  West 

End  New  Dam 

Corewall  East  End 

Excavation 

Footings,  Etc.  in  Bock 

Reinforcing  Steel 


Appurtenances 

Iron  Pipe  Bailings  

Bails  40  Ibs.  for  Derrick  2204  lin.  ft 

Ties  for  Track  720  6x8—8' 

Plank  for  Walkway  Top  of  Dam 

Walkway  and  Stringers 

Steel— Crest  Gates  Old  Dam  25  at  1195  Ibs. 

Crest  Gates  New  Dam  28  at  4020 

Trunions  and  Guides  

Sluice  Gates  5x6) 

Cylinders  ) 

Timber 

Crest  Gates  Old  Dam  

Crest  Gates  New  Dam  . 


Quantity      Unit 

787    Cu.  Yds. 
4,368      "       " 


8,230 

1,348 

593 

2,480 

586 

103 

289 

178 

170 

340 


90 

2,900  "       " 

7,000  "       " 

884,700  Lbs. 

2,313  Lin.  Ft. 

88,160  Lbs. 

23,040  Ft.  BM 

17,630  "       " 

7,870  "       " 

30,000  Lbs. 
110,000       " 

56  Number 

8 


Rate 


3,750 
23,800 


Ft.  BM 


625 

50) 
50) 


Amount 


$10 

$7,870 

12 

52,416 

12 

98,760 

12 

16,176 

12 

7,116 

12 

29,760 

12 

7,032 

12 

1,236 

12 

3,468 

12 

2,136 

12 

2,040 

12 

4,080 

10 

900 

10 

29,000 

2 

14,000 

5c 

44,235 

80c 

1,850 

5c 

4,408 

$50 

1,150 

50 

882 

50 

394 

5c 

1,500 

5c 

5,500 

$12 

672 

5,000 


1,378 


192  Report   on   the  Dam   at  Austin,   Texas. 

Concrete 

Crest  Gates  Old  Dam 20    Cu.  Yds.        12) 

Crest  Gates  New  Dam 65      "       "  12)  1,020 

Stair— Cast  Iron  Spiral  2     Number       275  550 

Erection  Crest  Gates  25  per  cent,  of  Esti- 
mated Cost 2,434 

Cofferdam  and  Pumping  100,000 


$446,963 
Contingencies,  10  per  cent 44,697 


Total   $491,660 

A  comparison  of  this  estimate  with  the  Cost  Keeper's  detailed  account  of  the 
actual  cost  of  this  work  will  show  the  cost  to  have  exceeded  the  estimate  by  about 
$50,000.  How  much  of  this  amount  may  be  due  to  the  inexperience  of  the  Contractor 
in  river  work  and  how  much  to  the  writer's  failure  to  make  proper  allowance  for  the 
necessary  cost  and  contingencies  of  the  work  he  is  unable  to  say.  The  writer  has  en- 
deavored however  to  make  a  fair  estimate  based  on  a  somewhat  extended  experience 
on  this  class  of  work,  and  his  estimate  must  be  considered  with  due  regard  to  the 
great  uncertainties  involved. 

EXTEA  WORK 

Various  items  for  extra  work  which  have  not  been  included  in  the  above  esti- 
mates are  found  in  the  Contractor's  Claim  for  Extra  Work.  In  the  following  table 
they  are  taken  at  the  actual  cost  figures  as  the  writer  has  no  other  method  of  esti- 
mating their  actual  cost  or  value. 


Estimates.  1 93 


EXTRAS  FROM  COST  KEEPER'S  ACCOUNTS 

Items  Amount 

Wiring  in  Dam $    6.43 

Signal  System  for  Sluice  Gates 22.58 

Wiring  in  Dam  Material 125.28 

Wiring  in  Dam  Labor   81.75 

Bell  Einging  Outfit   8.10 

Rock  Excavation  in  Tailrace  8,335.38 

Grouting  Top  of  Old  Dam,  2  holes  in  west  end 178.35 

Recording  Pressure  Gage 7.02 

Voltage  Regulator   430.78 

Sluice  Gate  Gages  Material 72.50 

Sluice  Gate  Gages  Labor  58.77 

Railings  on  Stairs   11.87 

Third  Pump  Unit 3,199.77 


$12,538.58 
Plus  10  per  cent 1,253.86 


Total   $13,792.44 

RECAPITULATION  OF  ESTIMATES 

Reservoir   $43,650 

Power  House,  Etc.  (Schedule  A)   37,773 

Machinery  and  Equipment  (Schedule  B) 99,624 

Dam    491,660 

Extras  13,792 


$686,499 

The  writer  believes  the  above  to  be  a  fair  and  reasonable  estimate  of  cost  of  the 
work  done  by  the  Wm.  P.  Carmichael  Company,  not  including  the  cost  of  repairs  and 
reconstruction  done  for  the  City  Water  Power  Company  on  account  of  faulty  design. 
Equitable  charges  for  such  work  are  a  fair  charge  against  that  Company  but  cannot 
be  considered  in  making  an  estimate  of  the  value  of  the  present  structures.  These 
charges  made  by  the  Contractor  for  extra  work  (see  page  197)  and  not  included  in  the 


194  Report   on  the  Dam  at  Austin,   Texas. 

writer's  estimates,  amount  to  $26,585.  The  difference  between  the  writer's  total  es- 
timate of  the  fair  cost  of  this  work  and  the  cost  as  shown  by  the  books  of  the  Wm.  P. 
Carmichael  Company  is  as  follows: 

Cost  from  Books  of  Wm.  P.  Carmichael  Company $795,332 

Writer's  Estimated  Cost  686,499 


Difference $108,833 

Carmichael 's  Claim  for  Extra  Work — Not  included   in  Writer's 
Estimate 26,585 


Difference  between  Writer's  Estimate  of  Cost  and  Cost  shown  by 

Carmichael  Co.'s  Books   $82,248 

Through  the  courtesy  of  Mr.  M.  C.  Andrews  of  the  Wm.  P.  Carmichael  Com- 
pany, the  writer  was  given  the  opportunity  of  examining  the  accounts  of  this  Com- 
pany. No  attempt  was  made  to  audit  the  books  as  such  an  audit  did  not  appear  es- 
sential for  the  purpose  of  this  report.  The  Cost  Keeper's  final  summary  of  the  ac- 
tual cost  of  the  work  was  however  abstracted,  and  is  as  follows : 

COST  OF  CONSTRUCTION  OF  AUSTIN  WATER  WORKS  RESERVOIR 
Cost  Keeper's  Account  Wm.  P.  Carmichael  &  Co. 

Lumber   $2,075.77  Minor  Equipment $     86.38 

Steel    2,491.51  Supplies    1,140.97 

Cement 10,346.70  Liability  Insurance 593.69 

Aggregate 7,727.81  Fire  Insurance 12.95 

Fuel,  Etc 227.79  Bond  Premium 234.24 

Rentals 330.83  Traveling  Expenses 128.36 

Labor 17,455.14  Nails  and  Wire 201.77 

Office  35.46  Hauling,  Etc 249.97 

Oils  and  Waste 21.79 

Iron  and  Steel  .  2.29  $43,363.42 


Contractor's  Costs. 


195 


COST  OP  SCHEDULE  A  (BUILDING,  ETC.) 
Cost  Keeper's  Account  Wm.  P.  Carmichael  &  Co. 


Lumber   

Cement    

Aggregate   

Fuel,  Etc 

Rentals    

Labor   

Steel   

Brick  and  Lime  . 
Window  Frames 

Handrail    

Explosives 

Slate  Contract  . . 
Crane  and  Track 

Plumbing 

Stone   . 


$1,495.43 

3,592.44 

2,099.04 

336.31 

781.88 

30,289.64 

513.45 

1,920.92 

189.79 

544.60 

466.86 

729.06 

1,820.24 

196.00 

46.00 


Painting 600.00 

Office  Expenses 189.92 

Oil  and  Waste 12.82 

Iron  and  Steel  105.62 

Bolts,  Nuts,  Etc 45.96 

Minor  Equipment 573.01 

Supplies  718.31 

Liability  Insurance  1,082.72 

Bond    144.39 

Traveling  Expenses 263.21 

Nails  and  Wire 86.84 

Hauling,  Etc 84.35 

Plant  Charges  3,741.91 


$52,670.72 


COST  OF  SCHEDULE  B  (PLANT  EQUIPMENT) 


Machinery   $62,919.90 

Lumber   287.09 

Steel   643.81 

Cement  1,310.68 

Aggregate   809.23 

Fuel,  Etc 181.67 

Rentals    595.40 

Explosives 8.93 

Labor 18,502.47 

Painting    140.00 


Office  Expenses 
Minor  Equipment  . . 

Supplies  

Liability  Insurance 
Bond  Premium  .... 
Traveling  Expenses 
Hauling,  Etc 


156.89 
155.87 
986.41 
858.76 
558.45 
193.39 
60.09 
Plant  Charge 5,376.43 


$93,745.47 


196 


Report  on  the  Dam  at  Austin,   Texas. 


COST  OF  RECONSTRUCTION  OF  DAM 
Cost  Keeper's  Account  Wm.  P.  Carmichael  &  Co. 


Lumber   $31,678.42 

Steel   17,190.20 

Cement   62,187.62 

Aggregate   21,981.77 

Fuel  and  Power 14,109.82 

Rentals 13,411.01 

Sluice  Gates  &  Bailings . . .  6,645.25 

Cableway 5,589.35 

Labor   317,427.84 

Explosives    5,187.74 

Office    2,765.22 

Oils  and  Waste  1,454.75 

Sheet  Metal  324.70 

Drill  Steel   1,144.74 

Iron  and  Steel 1,926.08 

Bolts  and  Nuts  1,251.96 

Minor  Equipment   12,325.07 

Supplies    9,470.88 

NOTE:    Total  cost  of  dam  only  given  on  page  198  dated  March  1,  1916, 
Amount  $545,725.46. 


Liability  Insurance 14,698.22 

Bond  Premium 2,271.81 

Fire  Insurance  179.49 

Traveling  Expenses 2,938.79 

Freight  on  Equipment 3,446.72 

B.  B.  Fares 665.99 

Nails  and  Wire 3,243.72 

Hauling,  Etc 1,091.21 

Labor   708.79 

Misc.  Material 316.87 

Forebay  Excavation,  Labor  301.30 


Total    $555,935.33 

Credit — Charged  'to  other 
parts  of  the  Work 10,249.67 


Total  Cost   $545,685.66 


** 
** 
** 


Contractor's  Costs.  1 97 

EXTRAS 
Cost  Keeper's  Account  Wm.  P.  Carmichael  &  Co. 

Item  Quantity  Kate  Amount 

**Wiring  in  Dam $  6.43 

**Signal  System  for  Sluice  Gates 22.58 

**Wiring  in  Dam  Material   125.28 

**Wiring  in  Dam  Labor  81.75 

**B.ell  Einging  Outfit  8.10 

Power  House  Account 121.38 

Equipment  Account  684.34 

Stanchion's  Crest  Gates  2,432.46 

Back  in  Head  Gates 2,192.11 

**Rock  Excavation  in  Tail  Race  8,335.38 

Grouting,  Etc.  Top  Old  Dam— 2  Holes  West  End 178.35 

Recording  Pressure  Gage 7.02 

Voltage  Regulator 430.78 

Retaining  Wall  (3d  Construction)  2,401.14 

Repairing  Crest  Gates 2,922.05 

Engineering— J.  G.  White  1,208.24 

*Paving  under  Draft  Tubes 233.70 

Platform  over  Rack 64.17 

Repair  Sluiceway  Arches  432.26 

Bronze  Strips  on  Sluice  Gates — Material 187.68 

Bronze  Strips  on  Sluice  Gates — Labor 477.21 

**Sluice  Gate  Gages— Material   72.50 

**Sluice  Gate  Gages— Labor  58.77 

*Corbels  on  Piers — Material  52.05 

*Corbels  on  Piers— Labor  128.27 

**Railings  on  Stairs   11.87 

Sluiceway  Arches 8,940.82 

Items  21,  24,  25,  26,  27 246.32 

Drift  Removal 1,097.26 

Diving 386.72 

Plus  Profit,  10  per  cent.  (4-7-15)   2,086.97 

20  per  cent 240.65 

Profit  (9-1-15)    1,067.11 


$36,944.72 
Less  Items  marked  as  Included  Elsewhere. .          414.02 


$36,530.70 

*  Included  in  Writer's  Estimate  of  Cost  of  Power  House. 
**Included  in  Writer's  Estimate  of  Cost  of  Extra  Work. 


198  Report  on  the  Dam  at  Austin,   Texas. 

Note  that  the  total  of  the  itemized  account  given  above  is  $646.54  short  of  the 
claims  for  extra  work  by  the  Wm.  P.  Carmichael  Co.  as  given  on  this  page.    This  is 

essentially  the  amount  of  the  extra  agreement  dated    2/29/16    given  thereon    and 
which  account  was  not  included  in  the  above  list. 

AUSTIN  DAM  COSTS  TO  MARCH  1,  1916 
(Wm.  P.  Carmichael  &  Co.) 

Dam $545,725.46 

Crest  Gates 19,036.09 

Eeservoir   43,363.42 

Schedule  A 52,670.72 

Schedule  B 93,745.47 

Extras  before  4/7/15 1,443.93 

Extras— Agreement  4/7/15  23,762.36 

Extras— Agreement  9/1/15  11,738.23 

Extras— Agreement  to  2/29/16  646.74 

3d  Pump  Unit 3,199.77 


Total  Cost   $795,332.19  $795,332.19 

Cash  Received: 

City  Water  Pr.  Co $261,640.07 

Bondholders'  Com 11,242.63          272,882.70 


$522,449.49  Present  W.  P.  C.  &  Co.  In- 
Amt.  Due  from  City  Water  Pr.  Co.  270,983.79  vestment 


$251,465.70  Construction  Loss.  To  get 
total  loss,  to  this  must  be  ad- 
ded General  Office  and  Interest 
Charges. 


APPENDIX  10 

RECOMMENDATIONS  OF  DB.  A.  C.  SCOTT — MARCH  31,  1915 

The  following  letters  from  Dr.  A.  C.  Scott,  Consulting  Engineer  of  the  City  of 
Austin,  outlines  the  betterments  which  he,  in  March  31,  1915,  considered  necessary 
for  the  completion  of  the  work. 

Apparently  no  action  was  taken  on  this  matter  by  the  City  Council  of  Austin,  and 
soon  after  the  April  flood  occurred  which  damaged  the  crest  gates,  filled  the  raceway 
and  caused  a  suspension  of  any  definite  action  on  the  part  of  the  City. 

March  31,  1915. 

Hon.  A.  P.  Wooldridge,  Mayor, 
Mr.  E.  C.  Bartholomew,  Councilman, 
Austin,  Texas. 

Gentlemen : 

In  accordance  with  your  instructions  and  the  request  of  Mr.  Rector,  City  Attor- 
ney, I  submit  a  statement  concerning  such  items  as  in  my  judgment  are  significant 
and  important  to  effect  the  complete  construction  of  the  dam  and  its  appurtenances, 
and  the  installation  of  power  plant  machinery  connected  therewith. 

1.  In  order  to  avoid  probable  future  trouble  in  the  operation  of  the  water  wheels 
a  stationary  forebay  rack  should  be  placed  in  front  of  the  head  gate  masonry,  ex- 
tending over  the  entire  space  occupied  by  the  inlets  to  the  three  penstocks,  and  to  a 
height  above  the  final  lake  level  being  placed  one  to  four  feet  in  front  of  said  mas- 
onry, which  will  allow  the  water  to  flow  through  said  rack  over  its  entire  area.    I 
would  suggest  that  this  rack  be  made  of  steel  bars  1^"  x  3"?  same  to  be  spaced  and 
held  in  position  %"  apart ;  or,  if  a  rack  of  equivalent  serviceability  be  constructed, 
same  would  be  satisfactory. 

2.  Six  of  the  sluice  gates  were  open  and  shut  yesterday   afternoon,    at   my   re- 
quest, and  were  found  to  be  readily  and  satisfactorily  operable.  Each  gate  was  tested 
individually;  it  was  first  fully  opened,  the  time  required  for  opening  being  about 
four  or  five  minutes ;  it  was  then  allowed  to  discharge  water  for  three  or  four  minu- 
tes at  the  full  opening  of  the  gate,  and  then  finally  closed.    About  five  minutes  in- 
tervened between  the  successive  intervals  of  the  openings  of  the  gates,  for  allowing 
the  water  to  drain  away  from  the  toe  of  the  Dam,  after  each  gate  was  closed.     No 
evidence  was  found  that  these  gates  do  not  open  readily  and  close  properly  and  com- 
pletely.    In  the  event  the  two  sluice  gates,  which  are  inoperable  at  present  be  not 
repaired  before  the  acceptance  of  the  dam  be  given,  the  City  of  Austin  should  be 
guaranteed  the  right  to  draw  down  the  lake  at  any  time  it  is  desired  to  repair  said 


200  Report  on  the  Dam  at  Austin,   Texas. 

gates  and  The  City  Water  Power  Company,  or  its  assigns,  should  agree  to  repair 
said  gates  at  its  own  expense,  at  such  time  as  the  lake  may  be  drawn  down  sufficiently 
to  do  so  for  that  or  for  any  other  purpose. 

3.  I  do  not  consider  that  a  concrete  tail  race  is  essential  provided  that  the  pres- 
ent natural  earth  tail  race  be  sufficiently  extended  in  width  to  permit  a  movement  of 
the  water  away  from  the  draft  tubes  of  water  wheels  Nos.  2  and  1,  which  is  compara- 
ble with  that  from  wheel  No.  3.     The  tail  race    should    be    deepened,    approximately 
three  feet.    If  the  tailrace  construction,  called  for  in  the  general  specifications,  be 
waived,  a  supplementary  contract  should  be  entered  into  between  the  City  Water 
Power  Company,  or  assigns,  and  the  City  of  Austin,  whereby  the  City  Water  Power 
Company  shall  agree  to  keep  the  natural  earth  tail  race  open  at  all  times  and  free 
from  drift  or  earth  and  rock  debris,  which  would  materially  decrease  the  effective 
head  upon  the  water  wheels.     Also  it  would  appear  that  this  contract  should  include 
an  agreement  to  the  effect  that  whenever  a  decision  of  three  hydraulic  engineers,  one 
to  be  appointed  by  the  City  of  Austin,  another  to  be  appointed  by  the  City  Water 
Power  Company,  or  assigns,  and  a  third  to  be  appointed  by  the  two,  shall  render  a 
majority  decision  that  the  City  of  Austin  needs  a  concrete  tail  race,  the  City  Water 
Power  Company  shall  build  same  at  its  own  expense  for  the  City  of  Austin,  or  agree 
that  the  City  of  Austin  may  build  such  concrete  tail  race  and  deduct  the  cost  thereof 
from  the  next  semi-annual  installment  to  be  paid  thereafter  under  the  general  con- 
tract. 

4.  The  west  end  of  the  old  Dam  must  be  grouted  from  the  top  to  stop  the  see- 
page through  same,  if  conditions  show  that,  after  drilling  holes  completely  through 
to  the  foundation  structure  of  this  part  of  the  Dam,  it  be  desirable  and  possible  to 
so  grout  the  structure  effectively. 

5.  A  recording  pressure  gage  should  be  properly  placed  within  the  Power  House 
and  suitable  connections  made  thereto  to  provide  a  daily  record  of  variations  in  the 
lake  level. 

6.  The  interior  finish  of  the  power  house  should  be  completed  (not  much  remains 
to  be  done  in  this  respect). 

7.  All  copper-aluminum  joints  made  in  lines  and  connections  of  electric  circuits 
should  be  clamped  independently  of  solder  (this  is  a  small  matter  to  be  completed). 

8.  The  "ground  wire"  in  pump  suction    should    be    differently    connected    to 
ground. 

9.  All  ground  connections  on  high  tension  line  should  be  complete  and  prop- 
erly made. 

10.  All  crest  gates  should  be  properly  staunched  to  prevent  further  than  reason- 
able leakage  over  the  Dam,  and  properly  balanced  to  operate  automatically  in  open- 
ing and  closing  within  one  foot  difference  in  the  lake  level. 

11.  A  concrete  floor  or  basin  should  be  placed  around  the  large  vent  pipes  near 
the  power  house  because  these  pipes  act  also  as  relief  pipes  for  the  water  and  same 


Recommendations  of  Dr.  Scott.  201 

flows  over  the  top  of  these  pipes  whenever  a  large  decrease  in  load  on  the  plant  oc- 
curs. This  concrete  floor  or  basin  should  be  properly  built  to  catch  such  overflow 
water  and  direct  it  over  the  retaining  wall  into  the  river. 

12.  The  draft  tubes  should  be  caulked  wherever  any  leaks  are  found  and  these 
tubes  should  be  painted  to  insure  their  durability  as  the  water  is  such  as  to  act  cor- 
rosively upon  unprotected  wrought  iron  or  steel  surfaces. 

13.  The  penstocks  within  the  power  house  should  be    cleaned    when    necessary 
and  coated  suitable  with  paint  or  other  material  to  preserve  them. 

14.  A  suitable  signal  system  should  ba  installed  extending  between  the  power 
house  and  the  inside  of  the  Dam  to  be  used  when  the  sluice  gates  are  being  operated. 

15.  The  clutch  pulley  which  drives  the  small  auxiliary  exciter  does  not  properly 
do  the  work  required  of  it,  and  same  should  be  put  into  satisfactory  serviceable  shape. 

16.  A  test  has  been  made  on  each  of  the  6600  volt  water  wheel  units  at  the  Dam, 
and  while  a  detailed  report  on  same  cannot  be  made  now,  because  of  insufficient  time 
to  make  it,  I  am  most  decidedly  of  the  opinion  that  the  efficiency  of  this  machinery  as 
a  whole  is  comparatively  high. 

The  motor  driven  pumps  have  not  been  tested  as  yet  because  of  delays  in  get- 
ting same  ready  for  a  test.  Such  delays  having  been  caused  by  a  combination  of  cir- 
cumstances over  which  I  had  no  control.  Data  obtained  during  a  few  short  runs 
made  on  the  pumps  to  put  them  in  shape  for  a  test,  indicate  that  they  will  meet  the 
efficiency  guarantees,  but  a  positive  statement  concerning  same  can  be  made  only  after 
test  data  have  been  obtained. 

With  reference  to  the  matter  of  a  conditional  acceptance  of  the  Dam  and  its  ap- 
purtenances, power  house  machinery,  etc.,  by  the  City  of  Austin,  before  the  above 
mentioned  items  shall  have  been  made  complete,  I  would  say  that  in  my  judgment  this 
remaining  work  to  be  completed  is  of  comparatively  small  magnitude  when  the  con- 
struction of  the  Dam  and  the  installation  of  the  machinery  together  with  the  building 
of  the  reservoir  as  a  whole  are  taken  into  consideration. 

It  is  further  my  conviction  from  an  engineering  standpoint  solely  that  none  of 
the  items  mentioned  is  one  which  likely  to  be  impossible  or  very  difficult  or  very  ex- 
pensive to  complete.  As  an  indication  of  the  cost  of  completion  as  a  whole  would  say 
that  undoubtedly  the  matter  of  less  than  $10,000  would  be  sufficient. 

From  an  engineering  standpoint  I  can  see  no  reasonable  objection  to  the  accep- 
tance of  the  Dam  and  its  appurtenances  as  thus  far  completed  under  the  general  con- 
tract, because  I  believe  that  good  material  and.  workmanship  have  been  put  into  the 
structure  and  installation,  and  that  same  will  be  durable  and  serviceable,  provided  that 
interests  of  the  City  of  Austin  can  be  satisfactorily  safeguarded  insofar  as  the  com- 
pletion of  the  balance  of  the  engineering  work  to  be  done  as  above  considered  is  con- 
cerned. 

Yours  very  truly, 

(Signed)     A.  C.  SCOTT. 


APPENDIX  11 

BIBLIOGRAPHY  OP  THE  AUSTIN  (TEXAS)  DAM 
(Arranged  in   Chronological  Order) 

Report  of  Jos.  P.  Frizell  on  the  proposed  dam  and  water  works  for  the  City  of  Aus- 
tin, Texas,  and  the  Consulting  Engineer's  Report.  March  26,  1890.  Published  by 
the  City  of  Austin. 

The  Colorado  River  Dam  at  Austin,  Texas,  Eng,  News,  July  11,  1891.  General  in- 
formation concerning  the  project. 

The  New  Water  Power  and  Water  Supply  at  Austin,  Texas.  Eng.  News,  Aug.  18, 
1892.  Extracts  from  Report  of  J.  T.  Fanning  on  the  project. 

Austin,  Texas,  Water  Works.  Eng.  Rec.  Aug.  27,  1892.  Notes  on  proposed  changes 
in  Design. 

Mr.  Fanning 's  Report  upon  the  dam  at  Austin,  Texas,  by  Jos.  P.  Frizell.  Eng.  News, 
Sept.  29,  1892.  Arguments  in  favor  of  the  original  design  and  comments  on  Mr. 
Fanning 's  Report. 

The  Austin  Dam  Controversy.  Eng.  Rec.  Jan.  21,  1893.  Extract  from  Annual  Re- 
port of  Austin  Board  of  Public  Works. 

The  Austin  Dam.  E.  W.  Groves.  Eng.  News,  Jan.  26, 1893.  Description  of  the  con- 
struction of  the  work.  This  issue  also  contains  the  report  of  the  Austin  Board  of 
Public  Works  for  the  year  1892. 

The  Austin  Dam  Accident.  Eng.  News,  June  29, 1893.  Report  of  failure  of  the  head- 
gate  masonry. 

The  Municipal  Power,  Light  and  Water  Works  of  Austin,  Texas.  Eng.  Record, 
July  1,  1893.  Description  of  project,  particularly  of  the  machinery. 

The  Colorado  River  Dam  at  Austin,  Texas.  Frank  E.  Snyder.  Eng.  News,  Aug.  2, 
1894.  General  description,  giving  quantities  and  costs  of  the  original  project. 

Annual  Reports  of  the  Mayor  and  Other  Officers  of  the  City  of  Austin,  Texas,  for  the 
year  ending  Nov.  30,  1895,  contains : 

Report  of  the  Board  of  Public  Works. 

Report  of  J.  P.  Frizell  on  the  proposed  dam  and  waterworks. 

Report  of  John  Bogart,  Consulting  Engineer. 

Report  of  Emile  C.  Geyelin. 

Report  of  J.  T.  Fanning  on  the  dam. 

Details  of  bids  received  and  contracts  awarded  on  the  various  items. 

Sanitary  reports  by  three  physicians  as  to  location  of  reservoir. 

Reports  on  electrical  system. 

Report  on  Flowage. 


Bibliography.  203 

Eighteenth  Annual  Report  of  the  Director.  U.  S.  Geol.  Survey,  Part  II,  1896-7, 
p.  193.  R.  T.  Hill  and  T.  W.  Vaughan.  Geology  of  Edward's  Plateau  and  Rio 
Grande  Plain  adjacent  to  Austin  and  San  Antonio,  Texas,  with  reference  to  the  oc- 
currence of  underground  waters. 

Twenty-first  Annual  Report  of  the  Director,  U.  S.  Geol.  Survey,  Part  VII,  1899-1900, 
by  Robert  T.  Hill.  Geography  and  Geology  of  the  Black  and  Grand  Prairies, 
Texas,  with  detailed  descriptions  of  the  cretaceous  formations  and  special  refer- 
ence to  artesian  waters. 

Municipal  Ownership  at  Austin,  Texas,  by  W.  D.  Hornaday.  Electrical  World  and 
Engr.  October  14,  1899.  Illustrates  and  describes  the  serious  condition  of  the 
Austin,  Texas,  dam  on  the  Colorado  River. 

The  Silting  up  of  Lake  McDonald  and  the  Leak  at  the  Austin  Dam.  Thos.  U.  Taylor. 
Eng.  News,  Feb.  22,  1900.  Information  relating  to  amount  of  silt  deposited  and 
illustrated  description  of  leaks  occurring  and  means  of  remedying  them. 

Failure  of  the  Great  Masonry  Dam  across  the  Colorado  River  at  Austin,  Texas.  Eng. 
News,  Apr.  12,  1900.  Illust.  description  of  break  of  April  7,  and  outline  of  pre- 
ceding troubles. 

The  Failure  of  the  Austin  Dam.  Eng.  Rec.  Apr.  14, 1900.  Illustrated  description  of 
the  construction. 

Failure  of  the  Austin  Dam.    Eng.  News,  Apr.  19,  1900.    Reports  of  the  failure,  by 

T.  U.  Taylor,  H.  M.  Chance  and  A.  B.  Roome. 

Failure  of  the  Austin  Dam.    R.  D.  Parker,  Eng.  Rec.  Apr.  21,  1900.    Illustrated 
description  of  the  failure. 
Thoughts  concerning  the  Austin  Dam  Failure.    Eng.  News,  Apr.  23,  1900.    Letter  to 

the  editor  discussing  effect  of  silt  on  the  stability. 
The  Failure  of  the  Austin  Dam.    Eng.  Rec.  Apr.  24,  1900.    Letter  by  Gardner  S. 

Williams,  suggesting  the  vacuum  beneath  the  nappe  as  a  contributing  factor. 
The  Failure  of  the  Masonry  Dam  at  Austin,  Texas.     Scientific  American,  Apr.  28, 

1900.     Brief  description  of  work  with  remarks  on  causes  of  failure. 
More  Light  on  the  Failure  of  the  Austin  Dam.     Thos.  U.  Taylor.     Eng.  News,  May 

10,  1900.     Discussion  of  causes  of  failure. 
Soundings  and  Measurements  at  the  Break  in  the  Austin  Dam.     Thos.  U.  Taylor. 

Eng.  News,  May  11,  1900.     Report  of  soundings  made  June  9,  1900. 
The  Austin  Dam  Failure.     C.  Baillairge,  Eng.  Rec.  May  19,  1900.    Urges  design  of 

dams  with  thickness  equal  to  height. 
The  Failure  of  the  Austin  Dam.    Wm.  Von  Rosenberg.       Eng.  Rec.  May  19,  1900. 

Illust.  description  of  erosion  at  the  toe. 
Some  Considerations  Regarding  the  Failure  of  the  Austin  Dam.    Eng.  Rec.  May  26, 

1900.    Editorial  discussion  on  importance  of  foundation  conditions. 


204  Report  on  the  Dam  at  Austin,   Texas. 

Speculation  suggested  by  the  Austin  Dam.  W.  E.  Hutton,  Eng.  Eec.  June  9,  1900. 
Discussion  of  effect  of  dam  overfall  upon  the  riverbed  below. 

Concerning  the  Austin  Dam.  B.  D.  Parker.  Eng.  Eec.  June  30,  1900.  Eeports  from 
various  sources  on  the  manner  in  which  failure  occurred  point  to  undermining  as 
probable  cause. 

The  Austin  Dam.  H.  B.  Patterson.  Eng.  Eec.  July  28,  1900.  Description  of 
causes  of  failure. 

Another  Communication  on  the  Failure  of  the  Austin  Dam.  Eng.  News,  Aug.  6, 
1900.  Letter  on  the  probable  causes  of  failure  by  McCarty  &  Son  and  comments  by 
T.  U.  Taylor. 

The  Latest  Soundings  at  the  Break  in  the  Austin  Dam.  Thos.  U.  Taylor.  Eng. 
News,  Dec.  6,  1900.  Eeport  of  investigations  made  Oct.  and  November,  1900. 

The  Austin  Dam.  T.  U.  Taylor.  U.  S  Geol.  Survey.  Water  Supply  Paper  No.  40, 
1900.  History  and  description  of  the  work,  specifications,  account  of  the  various 
accidents  and  failures  which  occurred  in  connection  with  the  original  structure, 
studies  of  the  silting  of  the  reservoir  and  report  of  soundings  made  after  the  dis- 
aster. 

Coefficient  of  Friction  in  Dam  Design  and  the  Failure  of  the  Dam  at  Austin,  Texas. 
H.  P.  Gillette.  Eng.  News,  May  30,  1901.  Discussion  of  theories  advanced  to  ex- 
plain failure. 

An  Estimate  for  Eebuilding  the  Austin  Dam.  Eng.  News,  Apr.  3,  1902.  Part  of 
report  and  estimate  submitted  to  City  of  Austin,  March  24,  1902. 

Geologic  Atlas  of  the  U.  S.  Austin  Folio,  Texas,  Eobert  T.  Hill  and  T.  W.  Vaughan, 
1902.  Geology  and  Topography  of  Edward's  Plateau  and  the  Coastal  Plain  with- 
in the  Austin  Quadrangle. 

A  Eeport  on  Eebuilding  the  Austin  Dam.  Eng.  News,  Nov.  12, 1908.  Extracts  from 
Eeport  by  Messrs.  Davis,  Hill  and  Taylor. 

The  Austin,  Texas,  Dam.  Eng.  News  Supplement  Nov.  14,  1908.  Comments  on  pro- 
posed plans  of  reconstruction  by  W.  G.  Kirkpatrick,  and  note  of  report  by  Messrs. 
Davis,  Hill  and  Taylor. 

The  Austin  Dam.     T.  U.  Taylor.     Bulletin  Univ.  of  Texas.     Dec.  22,  1910.     History 
and  description  of  the  work  and  extracts  from  various  reports  on  the  project  as 
follows :  J.  T.  Fanning,  Wilbur  F.  Foster,  Geo.  E.  Evans,  N.  Werenskold. 
This  Eeport  also  contains : 

Proposition  of  Consolidated  Construction  Co.,  Borings  at  Dam,  by  Kirkpatrick  and 
Blanton.  Eeport  of  Government  Engineers,  Messrs.  Davis,  Hill  and  Taylor.  Du- 
mont  Contract  or  Franchise. 

Designs  and  Contract  for  Eebuilding  the  Colorado  Eiver  Dam  at  Austin,  Texas.  Eng. 
News,  Apr.  14,  1910.  Eeviews  history  of  dam  and  gives  summary  of  contract  for 


Bibliography.  205 

reconstruction.     Gives  list  of  previous  articles  in  Eng.  News  pertaining  to  Austin 

Dam. 
The  Control  of  Water.     P.  A.  M.  Parker.  D.  Vanostrand  Co.  New  York,  1913.  pp. 

393  and  653.     Discussion  of  causes  of  failure. 

Reconstruction  of  the  Austin,  Texas,  Dam.     Eng.   News,   March   18,   1915.    Illus- 
trated description  of  the  reconstruction. 
Caverns  under  the  Austin,  Texas,  Dam.     Eng.  News,  Apr.  22, 1915.    Letter  by  A.  C. 

Blanton  concerning  borings  made  in  foundation  and  the  findings  based  thereon. 
The  New  Austin  Dam  and  Power  Plant.     Elect.  Eev.  &  W.  Elect  'n.     May  22,  1915. 

Description  of  certain  features  of  new  structure. 
The  New  Austin  Dam  and  Power  Plant.     F.  S.  Taylor.     Eng.  Cont.  May  26,  1915. 

Review  history  and  describes  new  plans. 
Hollow  Reinforced  Concrete  Structure  Replaces  Dam  at  Austin,  Texas,  which  failed 

15  years  ago.     Eng.  Rec.  May  29,  1915,  June  5,  1915  and  June  12,  1915.     History 

of  structure,  work  of  rendering  seamy  rock  impermeable,  and  detailed  description 

of  complete  work. 
Reconstruction  of  Austin,  Texas,  Masonry  Dam.     F.  S.  Taylor.     Eng.  News,  June  3, 

1915.  A  detailed  description  of  various  parts. 

Power  Development  at  the  Austin  Dam.     F.  S.  Taylor,  Eng.  News,  June  10,  1915. 

Description  of  headworks  and  machinery  installation. 
Some  Questions  about  the  Austin,  Texas,  Dam.     Eng.  News,  July  22,  1915.    Letter 

by  J.  D.  Dustin  concerning  reinforcement,  foundations,  etc.,  and  answer  by  F.  S. 

Taylor. 
Hydro  Electric  Power.    Lamar  Lyndon.     McGraw-Hill  Book  Co.  Inc.  New  York, 

1916,  p.  285.     Description  of  automatic  crest  gates. 

More  Trouble  at  Austin  Dam.  Eng.  News,  Apr.  6,  1916.  Remarks  on  further  dis- 
turbances with  special  reference  to  crest  gates  and  sluiceways. 

Austin  Dam  Section  Criticised.  Eng.  News.  Aug.  3,  1916.  Comments  on  extracts 
from  report  by  Bartlett  and  Ranney  on  the  change  in  design  of  the  reinforced  con- 
crete dam  section. 

The  Austin  Dam — Waterproofing  the  Rock  Foundation.  F.  S.  Taylor.  Municipal 
Engr.  Oct.,  1916.  Outline  of  history  and  description  of  work  to  prevent  leakage. 

Annual  Report  of  the  Water,  Light  and  Power  Departments  of  the  City  of  Austin 
for  the  years  1913,  1914,  1915  and  1916.  Contains  comments  and  accounts  of  var- 
ious points  concerning  the  construction  of  the  reinforced  concrete  dam. 


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LD  21A-50in-3,'62 
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